I agree with about 99.9% of the things mentioned on this thread, especially all the stuff about awful drivers.
It's not always the speed merchants who annoy me though. On the other end of the scale, it's annoying when you are driving on a 2 lane, max speed limit road & I always seem to get caught behind some slowpoke/tractor/lorry, etc!
Don't get me wrong, I like to think I'm a careful driver who sticks to the limits & so on, but for example, when the max speed limit's 60 mph & the car in front's doin 30 mph, it does cheese me off a little. Especially when the opposite lane's too busy to overtake!