As a BMW owner, I do think that more than other manufactuer's owners, BMW owners are more aggressive/douchbaggy.
That being said, there are tons of awesome BMW owners I've met and become friends with. But, if there is a person driving a car on the road that's driving as if it's entitled to cut you off, roll through a stop sign, peel out at a green light, etc. I would guess that it's a BMW
