9. Justin Bieber
Likely offense: Disturbing your morning runs with flagrant temper tantrums.
Lil' man gets a couple tattoos and he starts going H.A.M. on everybody. The pop star who still can't grow a mustache always seems ready to bust more than a grape in a fruit fight. With accusations of battery and threats to neighbors over sports cars, Bieber obviously hasn't learned to keep his disputes on the playground.