Sticking your arm outside the window to give the bird can be too much effort sometimes. Driv-e-mocion is the perfect device for the ultimate lazy aggressive driver. It is a small electronic display that can attach to the back window and allow any kind of message include smilie faces, frownie faces, kind words and even some four-letter words to be displayed. Given, the four letter words may anger the person behind you even more, it is still cool to put them in their place, geekily. $20 for an increased chance of being ran off the road, worth it to me.