...especially when they play BF2, and think they're pilots :\

Annoyance #1:
I hate when jerks steal the pilots seat in the bombers, when its quite obvious they dont deserve to be there. Sure, many are decent at flying (though many aren't), but they can't bomb anything if their life and their copilot's life depended on it (and sometimes they do, Anti-Aircraft missiles anyone?). Half the time they end up dogfighting with other planes, and getting killed because that's not what the bombers are meant for. Those missiles are for self-defence only!
And yet, they continue to take the seat, death after death, until it gets to the point where I feel like shooting them with the M95 before they can take off...but that would be rude (and often gets you kicked).

Annoyance #2:
I hate when those cocky bastards take it upon themselves to repeatedly bomb the uncapturable bases (9 times out of 10, an airbase) where all the people like to spawn, when many servers will BAN you for this. Even if there isn't a rule for it, it's still not right, it lessens the enjoyment for the rest of us. And yet, they will have the audacity to complain if you do the very same thing to them after you finally manage to shoot one down and send him back to his airbase.

Annoyance #3:
The one that I hate the MOST is people who teamkill for planes, or throw themselves infront of your plane so you teamkill them. Like, come on man...does the plane matter that much to you? If I get to it first, then too bad, wait for the next one.

Alright, this post became much longer than I wanted it to, so I will end my rant here.