I want to know what style of player pisses you off. And i'm not just talking about generic campers either.
I hate going up against a team of players in Domination who do nothing but use Extreme Conditioning + Quickdraw Pro + Steady Aim Pro with Tac Inserts. They keep rushing you, not caring how many times you kill them, until they kill you while you're reloading. Then they tac inside of the flag area and do nothing but ads the doorway/hallway for the rest of the game. If you kill them, they just poop out another tac and rush you some more. I still can't believe that these people can beat a team that's actually good by Zerging. I don't think that it's a cheap tactic, but I prefer actual strategy over mindless rushing.
I hate teammates more than anything. There isn't really anything an enemy is going to do that I'm not going to be able to counter rather quickly. Teammates are the absolute worst though. I don't know how many games I play where the game is literally two minutes in and somebody is already 0-10 and yet they continue to run into death over and over.
Or the people that seem to go completely out of their way to NOT play the objective. I want to reach through my TV and choke somebody everytime I jump on B by myself and a guy just either sits there and watches me try to solo cap until I die, or acts like he's going to cap the flag but runs right through it like Leeroy Jenkins.
This is an easy one. The wannabe good player. The player that plays every gamemode like teamdeath match. These players play objective gamemodes and camp the objectives for easy kills and killstreaks. They hardly ever play the objective because they are afraid to die.
They could play 2000 matches and lose them all and still be happy as long as their KD is over 2 or 3. Sadly probably over half the community plays this way.
I find that the sweet spot for good players to be between 1.4 to 2.2 KD ratio. I see the best play in objective game modes from these players. There are some really good players above this but there a very few of them. Many are scrubs like I described above.