Picture the scene. A quiet 3 lane motorway, lets say 6am sunday morning. I'm driving in the left lane, minding my own, when i approach another motorist in the middle lane, to my right, who i want to pass. There's no reason for him to be there, theres nobody else about. So i always make a point of moving behind them, into the outside lane, passing them, and moving back in front of them to the left lane (obviously while maintaining a safe distance, but doing it so they notice me doing it). Some people just dont get it. I can just picture them saying "well why doesnt he just drive in the outside lane?"