*People in who drive cadillacs are rated up there with the buicks for the slow driving.
*I hate parallel parking!
*Bonehead pedestrians who think they have the right of way when there's no crosswalk.
*People from out of state, or even worse, out of country. Some drivers from some states drive to slow, others too fast, and it is not that rare to see a foreigner driving on the OPPOSITE side of the road.
*This is not related to driving, but people who leave their college parking permits in their window since 1988 or have whole collection of them is annoying and tacky.