I have witnessed some truly spectacular examples of bad driving in the last week.
The worst by far was the car on the outside lane of the M3 who realised he was going to miss the junction he needed. So he stopped. In the outside lane. Then indicated left. Everyone had to stop to prevent a mass pile up so he very calmly just turned left and drove across all the lanes of traffic and then across the chevrons onto the slip road (where cars were still exiting at high speed). I truly hope that was caught on camera and he's hammered with points on his license!
On the same journey on a normal road (with a 60mph speed limit) a police car came up behind with blue lights on. All the cars on my side were slowing and pulling over (but not stopping) except the car in front which panicked at the last minute and just slammed the brakes on in the middle of the lane which caused the police car to have to drive on the other side of the road and everyone else to have to stop as well.
Some people shouldn't have a driving license!