I'm gonna do things outside of forums related stuff, just because I would be ranting for a while.
Major things:
Certain words being said
People being idiots
Smartasses
Things that happen every damn day
People that are overall annoying as forget
Minor things:
A certain team I don't like winning
People saying "Yes!" after they win
The major unnecessary use of ponies
The thing I hate the most:
Fandoms trying to make a game look bad.
No seriously. Take Undertale for example. That game is a fantastic game overall, but then there's that one person who is like, "OH THIS GAME IS BAD BECAUSE, WELL, JUST LOOK AT IT!" A bunch of people then get on the bandwagon, try to draw very cringeworthy art for the game, and then consider it a bad game. THen, when people see the artwork before they brought the game, they are going to join the bandwagon too, saying, "NOPE, NOT BEING LURED INTO THIS PIECE OF stuff". Eventually, they will overtake the game and make that game turn into a bad game just because of one stupid form of a fandom.
Seriously, sometimes I wish the internet did not exist.