Here's a few of my pet peeves.
Language W****s - I haven't seen it a lot, but it still annoys me. This is when people insult another person's language. Here's a recent example of this. I was looking through some comments on a Youtube video and one guy typed in "gray" and this one guy from the United Kingdom actually posts this, "It's spelt grey. Learn how to spell it correctly dumb***.". Yeah it is spelt grey in the United Kingdom, but the guy who typed in gray was from the United States and in the United States it is spelt gray. I also saw the almost the exact same thing with colour (British English) and color (American English). It's almost the exact same thing when I see someone type something in a different language and someone else just has to comment "Learn how to speak in [Insert language here], dumb***.", not everyone is going to know the same language and that is why it annoys me, knowing that these people haven't heard of the phrase "Different nationality" so they just think everyone knows the same language and then when someone doesn't they just have to call them a stupid. Another thing that I've seen that falls under the category, and I've been a victim of this, is when you insult someone who says the word y'all. I remember playing a game, and I can't remember where the guy was from, and he laughs at me just because I said the word y'all throughout the entire time I was forced to say you all. I can't help saying it, I was born and lived my entire life in Louisiana which is a southern state and a lot of southerners use the word y'all, and I hate the fact that not only did the guy say it was stupid for me to say that, but I really hate that I was forced to say "you all" or "all of you", it's something that I am not used to and I'd rather just say y'all since it means both.
"Same Difference" - It's like everyone I know is starting to use this phrase, a phrase that doesn't make a lot of sense. Pretty much if you ever use that phrase in front of me during an argument and you think that just by saying that it automatically means that you won the argument, well then you are a complete dumbox. I remember one time someone used this in front of me and they said "Chinese is the same as Japanese." to which I reply "No they aren't." to which they asked "Prove it" to which I proved that they are two different nationalities and the simple fact that, oh I don't know, that their languages sound extremely different when you compare them, that person then replied "That doesn't prove anything" to which I reply "Yeah it does prove something" to which they used "Same difference". First, be glad that I didn't get a knife from the kitchen and stabbed you to death with it for being racist. Second, what was it that you had to proved me wrong? Third, you used that prose where it doesn't mean any sense. It's like asking someone who says that a knife is the samething as a gun and then once I prove them wrong (Which really they are already wrong) they say "Same difference. So ha, I won this argument". No you didn't, you just made yourself look more like a jack***. The only time you should ever use the phrase "Same difference" is in a sentence like this "Ted and Tod fight because they have different religions. In other words they are fighting over the same difference.", that makes since since you're saying that they are fighting over the one thing that they both share in common that is different which would be their religion.
That's only a few.