I hate drugs and never touch them. I tried weed a couple of times a very long time ago and after it having no effect on me but seeing how retarded everyone else started acting I decided to stay well clear. I do have friends who socially use drugs and I'd never judge, what people choose to do with their bodies is up to them, and as long as I'm not directly effected by their actions I'm really not fussed but that doesn't mean I agree with their choices.
At the moment I don't drink and I've seen and experienced the consequences of too much alcohol. Essentially it is a drug and I probably wouldn't care if it was banned altogether (although I know there are larger issues around this). There should definitely be an age for drinking and I think it's fine as it is at 18.