If you've ever watched "The Sopranos" or the 1997 movie "Donnie Brasco," you might have wondered whether killing people is fun. After all, it seems fun to watch, at least on TV. Or maybe it's not the killing that's fun. Maybe it's the planning, the camaraderie, the petty squabbles, and the disdain for normal bourgeois existence that holds our attention. Demanding protection money and dealing drugs seems fun, too. If you've had such thoughts, have I got the social scientist for you.