Why are all the best things so bad for you?

It must be one aspect of intelligent design - the fact that what makes you feel good is bad for you. I remember reading a science-fiction novel (obviously written by a smoker) in which tobacco had been genetically modified to be anti-carcinogenic. The catch is that no-one would want to smoke.

The same applies to the only way I can even think about flying. After much research, discussion and stern warnings about how addictive it is, my doctor wrote out a script for a pretty powerful drug. In fact,