Ok in no particular order:
1. Parents who think their children can do no wrong, and don't expect them to take responsibility for anything. (can you tell I'm a teacher?)
2. The assholes in traffic who KNOW a lane is closing and everyone has formed this nice little polite line, and they speed up past the line to the merge point and nudge their way in.
3. Every last one of the morning radio DJ's in the DC metro area - good GOD I guess brains aren't required of that job around here.
4. People who get toooooooooo drunk toooooooo often and use that as an excuse for their constant assholish behavior.
5. Those damn "can you hear me now? GOOD!" commercials.
I think that covers the big ones.