Grown ups who act like kids....they cannot sit still, and have to get up every 10 minutes on some pretext or other. They did not bring anything to amuse themselves with such as an ipod or book, and instead sit and stare at the seat back, check their watch every 2 minutes, and rapidly pump their leg up and down..like fidgety kids, but grown ups who should know better.

Line jumpers of all kinds, old ladies are the worst of course, especially at the luggage check. And those who duck under line seaparators to get there before you.

Casual fliers who bring ridiculous crap with them onto the plane...like full sized pillows and coolers.

GAs and FA's who back down wayyyy to easily from folks who insist on pre-boarding (when they don't require it) or sneaking into F class. Why do I have to pay if they don't?

Seat poachers..doubly so for the ones who refuse to move..and worse are FA's who take their side.

Jestors who joke loudly to anyone in earshot, and to no one in particular and then laugh at their own quips. The kind of moron who thinks it's funny to tell tsa that his elderly mother has a bomb.

Drunks. Grow some balls and stop being afraid of flying. Alcohol won't help. It will only make you feel worse when you get there.