Do you sometimes tailgate cars driving at the speed limit (instead of 5-10mph over)?
My daily commute includes driving for about one mile on a winding road with double-yellow lines and a 30 mph speed limit. I tend to drive 35-40 mph on this road, and yet I'm often tailgated. It's like some people believe I do not have the right to drive the speed limit when they're in a hurry.
I've been on both sides of this issue. When I was younger I would often become incensed by slower drivers.