Riding my motorbike to work on a cold morning, I came up behind a car driving very very slowly through my residential area. I watched them slowly follow the road as it curved to the left, slowly keep turning left as the road straightened out, slowly drive up the curb and slowly hit a street light.
I pulled over to check on the driver as I was worried about it being a medical issue, but noticed they were already reversing. This made me think they might be drunk, so I moved a bit further away to put my bike behind a parked car, then went to check - by this time the driver was out of the car, not drunk or having any medical issues, just checking the car and then cleaning the windscreen. They had been too lazy to wait for the windscreen to de-mist a bit and had been trying to drive almost completely blind while wiping it with their hand...