People that will harp on someone's bad spelling without addressing any of the points they make
People that have absolutely atrocious spelling and grammar, and then when attacked they say "oh well SUE ME for not being ABSOLUTELY PERFECT"
Streets with names like "deer park", "meadow springs", "pine hills" - just stupid vague gated-community white-people bullshit
Gangster-types that wear crosses and/or have tattoos about God and/or honor and/or the Virgin Mary and/or love
Religious people that force their bullshit on you
People whose religions have been irrefutably proven to be full of shit (scientologists, mormons), but still participate in the religion
People that argue whether Macs or PCs are better - the two types of users want totally different things from their computers and the argument is therefore pointless
People who ignore every bad thing a celebrity has ever done as soon as that celebrity dies
People who don't realize the difference between "bad" and "objectively bad". Nacho cheese is awesome, but I am well aware it is objectively absolute trash. People should be smart enough to do the same with bad food, movies, pop music, etc. Nothing wrong with liking it, but admit that it's bad (I'm looking at you, Twilight fans).
People who think they're dropping a bomb on you by pointing out really obvious subtext
People who think they can teach you how to do something that they've personally never been able to do well
People who think their age, title, income, degree, or positive reviews makes them good at something. The only thing that makes you good at something is BEING GOOD AT THAT THING.
People that don't think rap is music. By every technical definition, opinions of professional musicians in the industry, conservatories/music schools, dictionary definitions, and even in historical context, it absolutely inarguably IS music. It's fine if you don't like it, you're still wrong, it's music.
Turn-based combat in games. If anyone is ever able to explain to me what's good about it, I might change my mind. No one has ever been able to explain why it's good.
People that think unintelligent people should be elected to public office. You don't want stupid people to EVER be handling anything else that affects your life, why do you want a stupid mayor/president/governor?
People who are removed from a position and/or publicly criticized for being involved in a scandal that in no way affects their ability to do their job well. Tiger Woods is a fucking golfer, who cares if he cheats on his wife. We never admired him because of his morals, we admired him because of his golfing.
People who make the same mistakes over and over again, and complain when they don't see different results.