I would also add just calling people by their name instead of their preference to your nickname example. Like, if your name is Matt but somebody only calls you Matthew and refuses to use Matt even after you ask them to. Matthew may legally be your name, but there’s only one reason why somebody would do that.
My dad actually has a similar situation in that his first name can be turned into two different nicknames easily, so he can immediately tell how well somebody knows him or cares by which name they call him.
I would also add just calling people by their name instead of their preference to your nickname example. Like, if your name is Matt but somebody only calls you Matthew and refuses to use Matt even after you ask them to. Matthew may legally be your name, but there’s only one reason why somebody would do that.
My dad actually has a similar situation in that his first name can be turned into two different nicknames easily, so he can immediately tell how well somebody knows him or cares by which name they call him.