BMW drivers, why??

Are these guys arrogant, or what? They always seem to need to show they have a fast car.

I was at a light when a 750-I pulled up beside me. His lane ended about an 1/8th of a mile from the light. Wouldn't you know it, he floored it at the green. So I did the same. He got the jump on me but I had him by two car lengths with the barracuda before the merge and still winding up. Man was he peeved off, I guess he's used to blowing people away.

This was not a residential area btw, or I would've let it go.