Grocery carts with one bad wheel that are wobbly, don't push smoothly, etc.
Drivers who don't use a turn signal
Couples who sit on the same side of the booth when there is no one on the other side. *People who sit next to you on public transportation even when there are other seats available. *Going through the drive thru, then having to go back when they screw your order up.
Whenever anyone says "Ya, know what I'm sayin"...
When a person makes that sucking noise with their straw when the cup becomes almost empty.