(in order of severity):
Scratched my phone's screen when I threw it down the side of a bed.
Broke a cereal bowl against the kitchen wall along with two weetabix and chocolatey milk when I threw it at my mother.
Took my doorframe clean out of the wall where I slammed it so hard, and broke the (admittedly very old) stone surround holding it in place, showering one end of my room in brickdust.
Threw my remote control at the wall. Remote control was fine (that's B&O for you), but it took an insulation panel straight off the wall, through the beams in my room and pushed a load of tiles off the roof in my room (my room is a loft conversion).
I don't loose my temper often, but when I do it goes big time. I used to have really big issues controlling it, but now it doesn't snap so easily. I think that's actually worse than how it used to be. When I was young I'd get angry but it wasn't at all severe. Now when I get angry, I go so mad my parents are afraid to come near me. We got a drum kit though, so that's good for venting my energy while playing...