People who attempt to DJ at parties or when you're in a car. And for some reason they never let a song get further than 1/2 over. Bonus points for people who play weird crap nobody has ever heard of, like everybody is going to just spin around and go "Man, this is great music!
...Then I ducked my head and the lights went out, and two guns blazed in the dark;
And a woman screamed, and the lights went up, and two men lay stiff and stark...
DJs who get really upset if you suggest that they aren't musicians. I mean, DJing is its own art form, sure, but if you're just up there putting on recordings of other people's music, you're not actually a musician. Sorry.
Also annoying is the way DJing seems to be the only thing leftover when people decide they want to be respected as musical performers but don't actually have any musical ability. I can't sing, I can't rap, I can't play an instrument...I got it, let's DJ!
Also it's fucking ridiculous how there are apparently 37 different definitions of "DJ", so when someone tells you he's a DJ you don't have a damn clue what he's talking about. Is he a disc jockey? Does he spin, or make mixes, or just play tracks at parties, or what? The term is becoming meaningless.
If you could be anything you want, I bet you'd be disappointed--am I right?