Some of mine:
* Talking on a cell phone while at the drive-through
* When I'm doing something with someone, and they take an unimportant call that lasts forever. "Yeah, I'm at Nekko's house. What are you doing? Oh, guess who I saw the other day..."
* Talking while at a store being helped by a salesperson and expecting them to keep helping while they talk
*People who are glued to their cells. Unless there are extenuating circumstances, there's no reason to be on a phone for 10 hours a day.