This happened to me yesterday. Saw a young couple with a baby stroller at a crosswalk, so I stopped and gestured for them to pass. They gestured back to let me pass. This goes back and forth a few times until they finally insist on letting me pass first. So I proceed through the crosswalk and just as I am getting through it, some idiot on the other side of the street jumps out into the crosswalk and nearly gets run over. I swerve to avoid collision and just as I am driving away, the idiot yells "F*ck you douchebag, your car sucks anyway!"
No matter what I do, I can never shake the BMW stereotype...