1. Reclining your seat.
2. Hogging the armrests
3. Being rude to the flight attendants.
4. People with giant carry-ons that take up too much space.
5. Talking too loudly.
6. Not waiting your turn to get off the plane after it lands.
7. Standing up multiple times during the flight to get stuff out of the overhead.
8. Putting your feet up by wedging them between the seats in front of you.
9. Loud swearing.
10. Hogging the window if you’re in a window seat, so the other people in your row can’t see out.
(wisebrother.com) (London city airport)