I've only been playing Call of Duty 4 online recently, but here's the comprehensive list of things that really annoy me about it.
1) Cheap Classes - People who run around with an M16 Grenade Launcher, RPG's, Sonic Boom and Martyrdom should be castrated. They don't know how to play the game, aim things properly, etc. and just run around taking random shots at things getting actually quite high scores.
2) The Irritating Perks - By these I mean Last Stand, Martyrdom and Juggernaut. All incredibly cheap, generally used by kids or people with low game knowledge, and are all put on this Earth solely to piss me off. Juggernaut especially.
3) Under-16 Players - Don't get me wrong, there are some kids who play the game who are cool and don't do anything to irritate other players online but then again the Disc case has a massive thing on it saying "16+". There are plenty of games rated "3+" and "12+" out there for them to be on. A lot of the time now, if some kid starts chatting crap during a game, I just file bad rep.
4) Prestige Mode - It's a total waste of time and effort. People who boast arrogantly about being 10-Prestige really annoy the living hell out of me because spending 40 days and nights locked inside in front of a television while the rest of us are out drinking beer and having fun shouldnt be anything to boast about. So what if they're level 550? Well done, I hope their parents are proud; Society, on the other hand, would struggle to care less.
5) Team-mates who ignore good advice - On too many occasions I've said something like "Dont go to A, its not safe" and then watched as my entire team march straight there anyway, to their painful deaths . In general, advice given over teamchat is given for a reason, people should realise this. Trying to co-operate with people can also be a nightmare, when I suggest strategies like "I'll keep an eye on the stairs while you watch the doors" and then we both get killed by someone coming through a door my team-mate was supposed to be watching. Perhaps he went to watch the "Riders on the Storm" music video on YouTube or something, but he certainly wasnt watching the doors I had in mind.
6) Helicopters - Calling in a Chopper is a great idea because whoever is flying the bloody thing and firing the guns always seem to be able to see/shoot through brick walls.
7) People who stand around doing bugger all - Ever been spectating the last one on your team left on Search and Destroy and he's standing there in an obscure corner of the map and has presumably run off to the toilet or something? Annoying, isnt it?
8) International arguments - The French dont always surrender in games, not all Americans are overweight, not all asians are terrorists, and not all brits contribute to their percieved bad dentistry by sitting around eating crumpets and drinking tea all damn day. Stop the International Stereotypes and needless arguments ... Its trivial, pointless and totally unneccesary.
9) People who copy my clan tag - What is the bloody point? The entire opposition team has changed their clan tag to match ours before ... but why bother? Its not offensive to us in any way, in fact, it shows their petulent stupidity and makes it even funnier.
10) Team-mates who get in the way - I dont even bother with silenced weapons/UAV Jammer etc. anymore, or hiding in long grass, because there will always be at least one bellend on my team who jumps up and down in front of my face or fires shots up in the air above me to give my position away on the enemy radar anyway. Then theres the ones who stand in a doorway and dont move to let their team-mates through, allowing their team-mates to be sniped in the back of the skull. But hey, thats what friends are for.
11) Shipment and Killhouse - I'd like to meet the pillock who designed these maps and strangle him.
12) Respawn Engine - Of all the places on the map that the game could respawn players, why is "directly on top of a live grenade" or "directly in front of bullet fire" such a popular choice? And why is it that in Headquarters, one team will always respawn on top of the headquarters, and the other will respawn half a world away?
13) Headquarters on Shipment against a team of 12-year old kids with grenade launchers - f**king kill me now!