Sit on an aisle seat that belongs to someone else.
Ask a lot of questions about a woman's personal life.
Try to read over someone's shoulder.
Fidget all the time, touching every part of your body from your hair, face down to your pants.
And finally, the worst of all, stick your elbow three inches into the seat next to you. [I was napping. Suddenly, I was poked at my left side, and I literally jumped. I cried out: "Excuse me!" Then, I vented out: "Lord!"]
ps. I didn't just hear about these. I was unfortunate enough to personally experience nearly all these during an 11-hour flight yesterday.