People who view overtaking lanes on motorways or dual carriageways as “fast lanes”, and either just sit in them when they aren’t overtaking (because they think they have a right to, as they are travelling “fast”), or get really impatient when a legitimate user of the lane is overtaking, but just not at as high a speed as they wish.
I don’t know about America (so I’m not intentionally directing this comment at the people above – your laws may be different), but I know that here in the UK no motorway lanes are speeded. They are for overtaking traffic only. I’ve just as much right to overtake as the next person, but I own a small car with a 998cc engine, so when I overtake it sometimes takes a whole few seconds longer. I don’t really see why I should sit behind a slow-moving lorry and never overtake because it takes my car a little while to get up speed. I obviously use the lane as courteously as possible, moving in when there is plenty of room and not causing anyone to slow down, and moving back out when I’ve finished overtaking, but get so sick of idiots that bear down on the rear of my car when my overtaking at 85mph in the outside lane isn’t fast enough for their 95+ motorway speeding.
Tailgating is definitely my most loathed driving peeve. It’s utterly selfish and dangerous. To be honest, I don’t mind people driving recklessly – if they end up wrapped around a tree or a brick wall because of their own idiocy, fair enough. I just can’t stand when people force their recklessness upon me. Other than making one appear childishly unable to control one’s aggression whilst at the wheel, I’m not quite sure what else tailgaing achieves.