One of my commuting goals is to pass motorists. I pass the slower moving ones but some motorists floor it when they see me approach on the side. Absolutely hilarious.
Did that the other day to a guy on a small motorcycle. He looked me, dropped behind for a bit to match pace (I think he wanted to know how fast I was going - about 40kmh at that spot as I remember and then shot off into the distance with a look of "thats impossible" on his face. Its more fun with the guys in big expensive cars stuck at traffic lights. Go around the traffic, cross on the pedestrian cycle and get home before they do.
You can just see them staring daggers at you.