I smoked pot when I was 18-20 (I'm almost 23 now). I liked it at first, but as I went along it became less and less enjoyable, and more and more paranoia and anxiety inducing. Not that I smoked that often anyways, only when I was offered it. I think if you're in a good mental state, pot is a great drug. That 18-20 period coincided with my anxiety etc kicking into high gear. So maybe someday, when I'm quite certain I'm happy and in a sound place, I'll occasionally indulge. For now, I don't see that day coming any time soon.

Two side notes: 1. I'm extremely afraid to try LSD (or whatever drug(s) you need to be in a good mental place to enjoy), because I know I will have a bad trip. 2. I kick ass at beer pong when I eat weed brownies. I can barely walk, but hot damn I can sink cup after cup like it's no one's business.

As for alcohol, that's a whole other issue. Suffice it to say, my family history and past drinking binges have convinced me drinking is just not a healthy choice for myself. The potential bad consequences far outweigh any benefits I may gain from it.