I believe that anyone who does non-medicinal drugs, abuses medicinal drugs, *cough* Heath Ledger *cough* smokes, drinks, or is fat should be laughed at. Repeatedly, with the following exceptions:
1. Fat people who are that way because of their body's natural growth. This mainly applies to old people.
2. Fat people who are actually in great shape, but just happen to look fat while they're at it. Includes sumo wrestlers, because at least they do some athletic activity.
3. People who are trying to get in better shape/loose weight. Unless they keep failing due to relapses.
4. Children under age 12. Because by age 12, they should know enough to be aware that they need to improve their health. Before that, their parents should have been trying to help them. Plus, some kids are just fat until they hit puberty. My brother went from the fattest of my mom's children to being our resident stick figure.
5. People who do drugs/smoke/drink with no known side-effects present. Mainly because it's so much funnier when they're in a position to realize the irony of their stupidity. Bonus points if they're STILL continuing their habit, thus proving that we should not offer them any real medical help. (except perhaps a therapist)