I remember once when I was living in London, my wife and I were riding home to Clapham from the city at what was for us a fairly moderate pace (about 20-25km/h). We were passed by a rapidly pedaling guy at about the halfway mark and thought nothing more of it until we saw him slow waaay down just up ahead of us. Maintianing our pace, we passed him fairly soon thereafter - that's how much he had slowed down. Almost immediately we saw him pass us again in the same frantically pedaling style, and again he slowed down just ahead of us allowing us to pass.

We played this little game of hopscotch pretty much all the way home, and every time he passed us our amusement just grew and grew. The look of concentration on his face was priceless.

I admit I've been guilty of giving terstosterone free reign at times, but it can also be quite amusing to observe it in others, especially when their ability doesn't quite measure up to their ego.