I'm genetically predisposed to be an alcoholic and substance abuser, but rather than saying "Whelp, guess it's inevitable, best start drinking a 5th of Jack a day and develop a pill addiction", I stay even more vigilant about not developing those addictions.  I've seen family members literally die from it, so I've never touched drugs outside of caffeine and I haven't had a drop of alcohol since shortly after my 21st birthday in 2006.