Drivers who sit in the passing lanes when the left hand lanes are clear. I honestly can't understand this, I go to work along a 3 lane motorway and there is a handful of traffic in the left lane moving freely yet the passing lanes are congested and moving slower than left lane. There's been times when I come on at the slip road and the car in front of me automatically moves to the lane furthest right even though the other lanes are clear. Dummies.