So I'm curious. How late do most people think is too late to call someone in the evening, if the person is not expecting a call from you? (And it's not an emergency, of course.)

To my mind, calling after 9 is starting to push it, if you're expecting it to be a long call.

Calling after 10 is right out.

I have this friend who almost never seems to call before 10. Am I just too much of a square? Or do other people think this is rude as well?