1.) Driving slowly in the left lane
2.) Rubbernecking
3.) Driving while doing things other than driving
4.) Cutting in line for the turn lane
5.) Not speeding up before, during, or after merging
6.) Blocking emergency vehicles
7.) Braking all the time in a jam
8.) Not using turn signals
9.) Pulling in front, then slowing down
10.) Not coping with an ending lane
the full article here:
The Ten Most Annoying Things People Do In Traffic