Drive Bys

Why is it that when someone in a car honks and waves, people stop to see who it is? Oh, I guess it could be Obama?

I work in a fairly large metropolis and on my way back from the gym this evening a cab honked it's horn several times and a person riding in the back stuck out his arm (pretty sure by the size and the hair it was a man) waving like a maniac. I'm thinking, like anyone is going to look long enough to figure out of the incessant noise and obnoxious wave is aimed at someine in particular, why don't you just have the cabbie stop and jump out for a second, or better yet whip out your cell phone, after all you are not driving! Well, to my utter amazement several people stopped to see who it was that was waving and honking.

What's up with that?