I have a friend that does it. He doesn't even screw with characters, he just says he's a fighter and smacks kids w/ 2X4s.
If you're talking about doing something a fictional person would do, I try out some of the scenarios I write on real people, or test stunts before committing them to paper.
most of my closest friends do it buy i make fun of them cause they're so loud and stupid but i sometimes do it when i have nothing to do or when i'm alone and have nothing close to read just to pass da time XD