I've never had a real nickname. My family used to call me Rob, for Robyn, but that sort of went away after I went to college. My boss calls me that and it used to annoy me until i had to do a writing piece about my name in a workshop. The workshop was run by a very good friend of my boss. When I read my piece, and I said it annoyed me when she called me Rob, the woman said I should tell her. I then realized it was stupid to be annoyed. She doesn't mean anything by it!
My uncle used to call me "Cousin Nybor," which is my name backwards. My younger cousins really liked that when they were little.