Reminds me of this -- http://www.xtranormal.com/watch/7873033/ (cartoon version of the theory of rational addiction) -- which you'll find especially funny if you hang out with economists much.

I haven't tried crack or heroin either but I wonder if they're more addictive than alcohol or tobacco or anything else that gives instant gratification. I tend to lean toward the addictive personality viewpoint. For instance I know people who can open a bar of chocolate and eat just a square or two. If I open a bar it's all gone