Fan Casting Do Not Call Me "Paul" in Sort by Tropes

This person does not like their birth name; if you call them by it, they will either correct you or ignore you. This could be for a number of reasons. They might feel that you are assuming too much familiarity with them. They might find their real name embarrassing (though their alias is not always much better). They could want to reinvent themself. Or it might be that no one calls them by that name besides their parents. Extra points if even their parents use their nickname unless they're angry with them.