Music elitists. I'll be honest here, I'm a huge one myself. Though I will say things like "Ugh, don't really like this band" I won't say stuff like "This band sux."

...At least I wouldn't do that unless they actually tried convincing me that their music was better than mine.

Actually, the fact that they're acting like music elitists isn't what actually bothers me the most; it's the fact that they suck at being elitist, 99% of the time, that bothers me the most.

(See sig for the three types of music with the most wannabe elitists that I've experienced)