When it comes to drinking, I'm more a social drinker. Generally not with family, except maybe a beer or glass of wine, but I don't get sloppy drunk. And really, I don't get sloppy drunk. I'm generally pretty in control, even when drunk, and I don't like the feeling of getting drunk and losing control. Tipsy is good enough.
Doesn't help that I know alcoholics. The less said on that, the better. Long story short, the best cure for a desire to drink is seeing others repeatedly make asses of themselves.
As for drugs, I haven't taken any. Ever. Been offered, but never tried any. And, I swear I had classmates, and probably even teachers, that probably thought I did drugs. Didn't help that I had friends that did drugs, and even they said I looked high as my default expression.
Anyway, I currently have a job that failing a drug test is a firing offense. Had it for a while and I can say I don't want to lose it. That's more than enough reason for me to avoid drugs. The loss of self control, doesn't help, either. Honestly, I don't need other reasons to avoid drugs, but that's enough.