Just thought I'd throw that out there for comments, for me it would have to be (in order):
1) Engineers who don't build teleporters which means the whole team has to spend 30 seconds or more getting to where the action is (e.g. from spawn all the way to Capture point C on er.. that map with 3 capture points)
2) Team members who when they see you doing well with a particular class, switch to it as well. Net result: 7 or so of one class on the same team, and then - predictably - the team stops doing well.
3) l33t speak - especially when its from someone who didn't even really contribute to his/her teams victory in any meaningful way.
1) Engineers who don't build teleporters which means the whole team has to spend 30 seconds or more getting to where the action is (e.g. from spawn all the way to Capture point C on er.. that map with 3 capture points)
2) Team members who when they see you doing well with a particular class, switch to it as well. Net result: 7 or so of one class on the same team, and then - predictably - the team stops doing well.
3) l33t speak - especially when its from someone who didn't even really contribute to his/her teams victory in any meaningful way.