Jumping over the seats in front of you at a baseball game in order to take away a foul ball from a 4-year old Being forced to listen to the local Top 40 radio station at work for hours on end disco
People who get in the express lane with too many items (although worse is the ones who go into the cash only line, and then after all the items are scanned, pull out a checkbook. Every single time, the cashier takes the check. Just once, I wish they'd say, sorry, wrong lane, and send the scum...