CAP irritates me. There's a start.
Here's part of the list:
Incompetent people, especially when it requires me to do parts of their job because they're idiots
Absolutely dumb people, especially the ones that run off at the mouth and have no idea what they're talking about
Slow drivers in my way
Drivers not using their turn signal
People that use X-Mas instead of Christmas
My wife most days
My boss every day
Someone saying something then when you ask what they said because you didn't catch it they say nevermind
My food order being wrong if I go through a drive through, I mean really it's not that hard
I know there's more just all I can think of right now.
Modified for below....
I GET IRRITATED BY PEOPLE YELLING AT ME ON THE BBS.