It really shouldn't bother me, and it kind of hasn't since college, but people who insufferably just latch on to the newest popular TV show or movie and don't seem to have any kind of taste, the kind of people who do shit like put Arrival into their top ten movies of all time. Like the guardians of the galaxy soundtrack was the worst example, because it ruined Moonage Daydream for a while since any college event or party I went to had that fucking soundtrack playing.
Guys who act like women being irrational is like an unavoidable thing you have to put up with if you date girls. I know a guy whose wife broke something of his and his only explanation for it was "she's a woman, she gets emotional" it's like they don't get that people are people and there can be normal and crazy ones.
And more than anything else, when somebody doesn't like something you've said but doesn't have the guts or common courtesy to just tell you themselves and tattletales to someone else about it. The older I get the more this pisses me off because it just instantly makes me lose respect for that person and makes me not want to socialize with them anymore. If you have a problem with me, fucking tell me, how else am I supposed to know when you don't give me any indication, don't be a pussy and go behind my back.