Ehh, I know how you feel. But weed virtually isn't as bad as you think, still letting a 13 or 14 year old do it bugs me. However, I can't complain I've been curious myself, yet it was only weed which I had a disliking for. This actually reminds me of my friend, he was a drug abuser. He told me of his adventures with Weed, Heroine, Ecstasy, acid. honestly the way HE described it, made it seem so interesting. I asked him the same thing: "Why?"
His answer: "to be with pleasure, feel genuine happiness, relieve stress."
I also do have a friend who is a drug abuser. Like honestly, when he talks it's instant you know.