Who Is This?

Quickie. I received a call fairly early this morning. The person on the other end proceeded to say "Who is this!?". What could I do? Just hung it up. How can people be so audacious as to call me and ask me who I am? That's worse than when a friend calls you and tells you to "hold on". How about the standard greeting of "hi" or "hello"? I was always taught to drop a greeting, my name, and a polite request to speak to the person I was trying to reach. Guess they don't teach that everywhere. Fail.