I don't think it is really a question of "vanity," to try to make something look more interesting than a bunch of randomly selected numbers and letters sticking out on a big sign attached to the front and rear of one's car. Maybe some people use it for vanity, but many just try to add a lil' intelligence or fun to a rather obnoxious and ugly feature on all cars. But then again some guys can't even recognize that a license plate is obnoxious and ugly looking.
