Twats who pull out in front of you, then fucking dawdle. If you're gonna pull out on someone, at least make an effort and floor it.
Even worse, someone pulls out in front of you, causing you to brake. So you look in the mirror, and nobody behind you. So not only is that twat a bad driver, he can't even see beyond you as you approach. Wankers.
Cunts who sit on your arse on the motorway, despite visibility being poor. The 2 second rule should somehow be measured, and fines given out to tailgating pricks.