It is frightening and incomprehensible. Earlier this week we were coming away from an antiques fair at a local race course. The racecourse exit is about half mile from the nearest main road on small residential roads. There were some road works on this minor road with traffic lights so traffic was moving at less than walking pace as we queued for the traffic lights.
Suddenly the driver of the second car in front of us jumped out and came up to the drivers door of the car in front and began shouting, before going back to his car. I found quite impossible to think of anything the driver in front could have done to engender this response. Certainly, from behind, he seemed to be just moving with the queue, not jockeying or trying to overtake, which was anyway impossible.