You've never walked into a room and seen your friend dead with a rifle in his hands. Thank crystal for that.
You've never had friends rob friends to get another hit. You've never seen girls whoring themselves out for drugs. Multiple kids left at family's houses while they turn tricks for more rock.
There are a lot of things I saw at your age that didn't prepare me for what was to come years after these peoples drug use.
Many of my friends from my teens just walk the street, crash at a house of a friend. Stealing and robbing, in and out of jail constatnly. Sure 10 years ago they had it under control, but after a while these drugs take control. That next hit might be the one that locks you into to that particular hard drug. Moderation really doesn't have much to do with it. I've had casual users turn to fiends within a month.
I've seen how shady these people get, what they're willing to do. It's a cold world when a man is willing to suck anothers dick for cash. I doubt they'd even consider themselves gay, they want the rock.
18 is cool, it's still experimenting, 25 isn't, its habbit, and one that isn't as easy to kick. most of the fiends I know are heavy into the religion trying to come back, I only 2 people that have come back. One is a minister, the other works at rehab.
Your age is your ignorance, I think you should take a step back and accept the fact that these drugs are considered dangerous for a reason, not to be debunked by some kid who has just become enlightened to the effects of them.