Just read about Carmelo Anthony's punishment for throwing a punch in the Knicks-Nuggets figh^H^H^H^H game. Apparently, Carmelo had recently taken up boxing in the off-season.
The really bad thing about a little training is that you feel like you know what you are doing in a fight situation. But you don't. You're too new at it and you're just thinking about the immediate problem (guy in your face), and not thinking about it with respect to everything else in your life.