I've been seeing that too. I guess once you get away with it you start to make a habit of it.

To be fair (not that these aggressive drivers deserve it), it's hard to tell when a car is stopped ahead of you if it's for a good reason and you should be patient, or if it's someone who just decided they can come to a stop in traffic for the hell of it. I try to assess the situation first at least, rather than just immediately blast around.