Have taken refuge in a bar now but what behaviour annoys you at the airport?
My top 2:
People who walk passed the multiple signs at Heathrow telling them about the rules on liquids (written and pictorially) and express outrage when said liquids get confiscated or they spend ages already at the conveyor belt digging out all of their little bottles.
On the otherside of security the people who, instead of moving their tray to the little cubicles designed for the purpose, they stand at the exit to the baggage scanner putting on shoes, belts, watches etc causing a backlog through the people scanner.