- Not using turn signal until they're practically stopped (signal before you break, people)
- Not using turn signal at all
- Driving too closely behind me, especially at higher speeds. (3 seconds between you and the car in front of you. I make a point to count the seconds sometimes - pick a spot and count how long it takes you to reach it after the car in front of you)
- Pulling out in front of me - and then turning a half mile down the road.
- Not accelerating up to the speed limit because they're turning in a mile or two.
- Not stopping at stop signs ([almost] everyone rolls through a stop sign sometimes, but blowing right through one? You're gonna cause an accident)
- Driving slow in the fast lane.
- Driving so slowly I can pass them going under the speed limit.
This list is by no means exhaustive - I'm sure I could think of more things if I put the time in.