Better to draw a giant dick on the windshield in lipstick or eyeliner. No permanent damage, the point gets across, and it's a bitch to get off properly. Never did it myself but I watched an adult woman do it (as a child) and it struck me as such a clever way to get back at an asshole without being a bigger asshole. (Full disclosure, she wrote "bitch" in huge letters across the windshield, but I think drawing a dick is funnier)