Stopped his car in the middle of the car park to have a go at a pedestrian who got too close to his precious BMW. When I asked him (politely!) to move his car, he took umbrage at this and kept flinging his fingers up in the air in the sign language of BMW drivers. Poor thing probably didn't understand me since I used words containing more than one syllable...
Chopping and changing lanes, undertaking and tailgating on the M1!