Well Corpsers, Brumaks, the Giant Worm, and Kryll tend to grind my Gears
But Gears of War jokes aside.... When people are overly condescending towards characters or more importantly other people. I can respect that you don't like something and explain it, but when you start tacing on the little comments or placing blames and the ever popular 'useless/one dimensional' tags it's upsetting.
There are people who like those characters and it honestly can be disheartening to see them insulted.
But that's mostly on here. The largest thing I do not like is when people are cruel to other people....it's the worst.
...and Organic Chemistry exams.