diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/BooleanFormatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/BooleanFormatter.cs
index 7beb865..90385e5 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/BooleanFormatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/BooleanFormatter.cs
@@ -27,13 +27,13 @@ public class NullableBooleanFormatter : IYamlFormatter<bool?>
 
         public void Serialize(ref Utf8YamlEmitter emitter, bool? value, YamlSerializationContext context)
         {
-            if (value == null)
+            if (value.HasValue)
             {
-                emitter.WriteNull();
+                emitter.WriteBool(value.GetValueOrDefault());
             }
             else
             {
-                emitter.WriteBool(value.Value);
+                emitter.WriteNull();
             }
         }
 
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/ByteFormatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/ByteFormatter.cs
index 18dcbc0..0a026fd 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/ByteFormatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/ByteFormatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, byte? value, YamlSerializatio
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/CharFormatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/CharFormatter.cs
index cfc92bf..4a91ff0 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/CharFormatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/CharFormatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, char? value, YamlSerializatio
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/DateTimeFormatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/DateTimeFormatter.cs
index 0f447bf..ad99b5c 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/DateTimeFormatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/DateTimeFormatter.cs
@@ -56,7 +56,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, DateTime? value, YamlSerializ
             if (value.HasValue)
             {
                 var buf = context.GetBuffer64();
-                if (Utf8Formatter.TryFormat(value.Value, buf, out var bytesWritten, new StandardFormat('O')))
+                if (Utf8Formatter.TryFormat(value.GetValueOrDefault(), buf, out var bytesWritten, new StandardFormat('O')))
                 {
                     emitter.WriteScalar(buf[..bytesWritten]);
                 }
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Float32Formatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Float32Formatter.cs
index 6523a05..279c033 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Float32Formatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Float32Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, float? value, YamlSerializati
         {
             if (value.HasValue)
             {
-                emitter.WriteFloat(value.Value);
+                emitter.WriteFloat(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Float64Formatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Float64Formatter.cs
index 54ef6b0..75e2d14 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Float64Formatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Float64Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, double? value, YamlSerializat
         {
             if (value.HasValue)
             {
-                emitter.WriteDouble(value.Value);
+                emitter.WriteDouble(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int16Formatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int16Formatter.cs
index b426b61..d28643b 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int16Formatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int16Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, short? value, YamlSerializati
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int32Formatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int32Formatter.cs
index e4be1c8..bb2c75e 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int32Formatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int32Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, int? value, YamlSerialization
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int64Formatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int64Formatter.cs
index 555c2e6..cd1fbd7 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int64Formatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/Int64Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, long? value, YamlSerializatio
         {
             if (value.HasValue)
             {
-                emitter.WriteInt64(value.Value);
+                emitter.WriteInt64(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/NullableFormatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/NullableFormatter.cs
index 54d5b94..2ee6161 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/NullableFormatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/NullableFormatter.cs
@@ -44,7 +44,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, T? value, YamlSerializationCo
         {
             if (value.HasValue)
             {
-                underlyingFormatter.Serialize(ref emitter, value.Value, context);
+                underlyingFormatter.Serialize(ref emitter, value.GetValueOrDefault(), context);
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/SByteFormatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/SByteFormatter.cs
index c53add8..d4c676b 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/SByteFormatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/SByteFormatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, sbyte? value, YamlSerializati
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt16Formatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt16Formatter.cs
index 6419ad2..4403aca 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt16Formatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt16Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, ushort? value, YamlSerializat
         {
             if (value.HasValue)
             {
-                emitter.WriteUInt32(value.Value);
+                emitter.WriteUInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt32Formatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt32Formatter.cs
index c968dcf..8c14889 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt32Formatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt32Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, uint? value, YamlSerializatio
         {
             if (value.HasValue)
             {
-                emitter.WriteUInt32(value.Value);
+                emitter.WriteUInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt64Formatter.cs b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt64Formatter.cs
index e2e4754..73bd78f 100644
--- a/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt64Formatter.cs
+++ b/VYaml.Unity/Assets/VYaml/Runtime/Serialization/Formatters/UInt64Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, ulong? value, YamlSerializati
         {
             if (value.HasValue)
             {
-                emitter.WriteUInt64(value.Value);
+                emitter.WriteUInt64(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/BooleanFormatter.cs b/VYaml/Serialization/Formatters/BooleanFormatter.cs
index 7beb865..90385e5 100644
--- a/VYaml/Serialization/Formatters/BooleanFormatter.cs
+++ b/VYaml/Serialization/Formatters/BooleanFormatter.cs
@@ -27,13 +27,13 @@ public class NullableBooleanFormatter : IYamlFormatter<bool?>
 
         public void Serialize(ref Utf8YamlEmitter emitter, bool? value, YamlSerializationContext context)
         {
-            if (value == null)
+            if (value.HasValue)
             {
-                emitter.WriteNull();
+                emitter.WriteBool(value.GetValueOrDefault());
             }
             else
             {
-                emitter.WriteBool(value.Value);
+                emitter.WriteNull();
             }
         }
 
diff --git a/VYaml/Serialization/Formatters/ByteFormatter.cs b/VYaml/Serialization/Formatters/ByteFormatter.cs
index 18dcbc0..0a026fd 100644
--- a/VYaml/Serialization/Formatters/ByteFormatter.cs
+++ b/VYaml/Serialization/Formatters/ByteFormatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, byte? value, YamlSerializatio
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/CharFormatter.cs b/VYaml/Serialization/Formatters/CharFormatter.cs
index cfc92bf..4a91ff0 100644
--- a/VYaml/Serialization/Formatters/CharFormatter.cs
+++ b/VYaml/Serialization/Formatters/CharFormatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, char? value, YamlSerializatio
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/DateTimeFormatter.cs b/VYaml/Serialization/Formatters/DateTimeFormatter.cs
index 0f447bf..ad99b5c 100644
--- a/VYaml/Serialization/Formatters/DateTimeFormatter.cs
+++ b/VYaml/Serialization/Formatters/DateTimeFormatter.cs
@@ -56,7 +56,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, DateTime? value, YamlSerializ
             if (value.HasValue)
             {
                 var buf = context.GetBuffer64();
-                if (Utf8Formatter.TryFormat(value.Value, buf, out var bytesWritten, new StandardFormat('O')))
+                if (Utf8Formatter.TryFormat(value.GetValueOrDefault(), buf, out var bytesWritten, new StandardFormat('O')))
                 {
                     emitter.WriteScalar(buf[..bytesWritten]);
                 }
diff --git a/VYaml/Serialization/Formatters/Float32Formatter.cs b/VYaml/Serialization/Formatters/Float32Formatter.cs
index 6523a05..279c033 100644
--- a/VYaml/Serialization/Formatters/Float32Formatter.cs
+++ b/VYaml/Serialization/Formatters/Float32Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, float? value, YamlSerializati
         {
             if (value.HasValue)
             {
-                emitter.WriteFloat(value.Value);
+                emitter.WriteFloat(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/Float64Formatter.cs b/VYaml/Serialization/Formatters/Float64Formatter.cs
index 54ef6b0..75e2d14 100644
--- a/VYaml/Serialization/Formatters/Float64Formatter.cs
+++ b/VYaml/Serialization/Formatters/Float64Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, double? value, YamlSerializat
         {
             if (value.HasValue)
             {
-                emitter.WriteDouble(value.Value);
+                emitter.WriteDouble(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/Int16Formatter.cs b/VYaml/Serialization/Formatters/Int16Formatter.cs
index b426b61..d28643b 100644
--- a/VYaml/Serialization/Formatters/Int16Formatter.cs
+++ b/VYaml/Serialization/Formatters/Int16Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, short? value, YamlSerializati
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/Int32Formatter.cs b/VYaml/Serialization/Formatters/Int32Formatter.cs
index e4be1c8..bb2c75e 100644
--- a/VYaml/Serialization/Formatters/Int32Formatter.cs
+++ b/VYaml/Serialization/Formatters/Int32Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, int? value, YamlSerialization
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/Int64Formatter.cs b/VYaml/Serialization/Formatters/Int64Formatter.cs
index 555c2e6..cd1fbd7 100644
--- a/VYaml/Serialization/Formatters/Int64Formatter.cs
+++ b/VYaml/Serialization/Formatters/Int64Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, long? value, YamlSerializatio
         {
             if (value.HasValue)
             {
-                emitter.WriteInt64(value.Value);
+                emitter.WriteInt64(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/NullableFormatter.cs b/VYaml/Serialization/Formatters/NullableFormatter.cs
index 54d5b94..2ee6161 100644
--- a/VYaml/Serialization/Formatters/NullableFormatter.cs
+++ b/VYaml/Serialization/Formatters/NullableFormatter.cs
@@ -44,7 +44,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, T? value, YamlSerializationCo
         {
             if (value.HasValue)
             {
-                underlyingFormatter.Serialize(ref emitter, value.Value, context);
+                underlyingFormatter.Serialize(ref emitter, value.GetValueOrDefault(), context);
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/SByteFormatter.cs b/VYaml/Serialization/Formatters/SByteFormatter.cs
index c53add8..d4c676b 100644
--- a/VYaml/Serialization/Formatters/SByteFormatter.cs
+++ b/VYaml/Serialization/Formatters/SByteFormatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, sbyte? value, YamlSerializati
         {
             if (value.HasValue)
             {
-                emitter.WriteInt32(value.Value);
+                emitter.WriteInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/UInt16Formatter.cs b/VYaml/Serialization/Formatters/UInt16Formatter.cs
index 6419ad2..4403aca 100644
--- a/VYaml/Serialization/Formatters/UInt16Formatter.cs
+++ b/VYaml/Serialization/Formatters/UInt16Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, ushort? value, YamlSerializat
         {
             if (value.HasValue)
             {
-                emitter.WriteUInt32(value.Value);
+                emitter.WriteUInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/UInt32Formatter.cs b/VYaml/Serialization/Formatters/UInt32Formatter.cs
index c968dcf..8c14889 100644
--- a/VYaml/Serialization/Formatters/UInt32Formatter.cs
+++ b/VYaml/Serialization/Formatters/UInt32Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, uint? value, YamlSerializatio
         {
             if (value.HasValue)
             {
-                emitter.WriteUInt32(value.Value);
+                emitter.WriteUInt32(value.GetValueOrDefault());
             }
             else
             {
diff --git a/VYaml/Serialization/Formatters/UInt64Formatter.cs b/VYaml/Serialization/Formatters/UInt64Formatter.cs
index e2e4754..73bd78f 100644
--- a/VYaml/Serialization/Formatters/UInt64Formatter.cs
+++ b/VYaml/Serialization/Formatters/UInt64Formatter.cs
@@ -29,7 +29,7 @@ public void Serialize(ref Utf8YamlEmitter emitter, ulong? value, YamlSerializati
         {
             if (value.HasValue)
             {
-                emitter.WriteUInt64(value.Value);
+                emitter.WriteUInt64(value.GetValueOrDefault());
             }
             else
             {