While the article's a bit old now, the 17 worst indignities that you suffer on a plane listed by CNNGo are still very valid. Love the graphic from the article!
Travel Tip: If you are stuck next to someone that is seriously overweight, complain to the stewardess after the airplane has taken off and away from your seat. Be polite and apologetic to the woman, and you may even get an upgrade if the flight's relatively full. Resist the urge to make loud comments about some people being forced to buy two seats.