Let's see...
I hate people who don't remember our history. On Dec. 7th last year, I was the only person on both my facebook and at my school who even remembered that it was Pearl Harbor day. The same thing happened on June 6th(D-Day), July 1st (Battle of the Somme), June 4th (Midway), and a couple others I don't remember...
I hate American politics, it takes too long for them to decide on anything and once they do decide, they side with whoever will get them re-elected.
I hate anti-gun activists, they don't understand what they're doing. To sum it up in a single sentence, "If you ban guns, only criminals will have them."
Those are really just my top three, there's more things but they're not worth bringing up.
I just remembered something else
Half-Life fanboys/Valve fanboys. Yes, many games could be seen as mods of HL, that doesn't mean you have to say it every, single, fucking, time. Yes, it's a good game. The best? Hell no. The only reason it can be seen as good is because of the grav gun and the massive ability to mod. In my opinion, the plot sucks and there's little to no characterization.