Here in New England I see many things and I have picked up some bad habits as well. These are the things that bother me the most.
1. People that only drive in the left lane on a multi-lane road.

2. People who are distracted and don't drive a constant speed because of the distraction.

3. People who turn left on a busy road and don't signal until the light turns green.

4. People who try to make a single lane into two lanes to cut other cars off.