While looking for something completely different on the Chicago Tribune's website I ran into this article reprinted from the Washington Post. This is the gist of it:
Watch out for cars with bumper stickers.That's the surprising conclusion of a recent study by Colorado State University social psychologist William Szlemko. Drivers of cars with bumper stickers, window decals, personalized license plates and other "territorial markers" not only get mad when someone cuts into their lane or is slow to respond to a traffic light, they also are far more likely than others to use their vehicles to express rage —by honking, tailgating and other aggressive behavior.
My initial reaction was the same as it is to most things in the WashPost: "that's nuts." But I reconsidered and thought that ol' Szlemko just might be on to something. So, I did my own quick research and found that, sure enough, 75% of people with bumper stickers on their cars are stark ravin' crazy and should be avoided at all costs by the sane among us. The other 25% loves them some John Cash.