Comment by DarkNova6

I've been let down by structs in C# repeatedly. First of all, there are no constructor guarantees and you can never fully avoid them representing an illegal state. Which, wouldn't be so bad if there was some kind of post-construction validation, but this also isn't part of the language.

This is fine if you hand-roll all your code yourself, but I often use mapping libraries to lower the code footprint and the problems resulting from schema changes are subtle and fly under the radar. This is different from classes with hard construction guarantees, which Java would offer with their "integrity by default" mantra. Where you can opt out of integrity for performance benefits (which is also part of the design).

And Nullability in C# is an absolute nightmare. The type system has completely different rules for nullable types that generalize over classes and structs and there is no generic such as a "Nullable type".

It's just lots of minor annoyances that don't form a cohesive whole.