I'm driving a tractor at 10 km/h past parked cars. The driver suddenly opens the door right in front of me, and I hit it. He gets out and asks, "Didn't you see?" I reply, "You opened it right in front of me." He's even more indignant: "Where are you going?" "I'm going 10 km/h." He barely manages to close the door. But then a Lada 2109 comes flying around the corner.