I used to be a bit of a cokehead. Other than that I've only done acid, shrooms and opium. I very rarely smoke ganja though (only when I'm already fucked up and someone else offers). Weird. I've also been a drunk since I was 12 and used to bring an Icy Tea container (it's cold, suger enchanted to the point of being almost like a milkshake, lemon tea that only seems to be available locally) half filled with Jack Daniels to school every day. Now that's dedication.
The only time that I've ever had a negative experience with anything was about 3 months ago with mushrooms. Three friends and myself each took an 8th, but me and one of my friends ate ours in a little too much of a hurry. After about 10 minutes I knew something was wrong, as I shouldn't have been feeling anything that soon. He started pacing and going upstairs and coming back down and going back up and saying that he didn't feel good. That amplified my own problems. Then we went outside for some air and everything just fucking broke out there. We were in a panic. My heart was pounding and I thought I was dying. We tried drinking a ton of water to "dilute" it. That didn't work. We tried to force vomiting. That made it worse. We tried sitting in dark rooms. Worse. Then he starts telling us that he needs an ambulance. I fucking freaked and though I was going to get my stomach pumped and go to jail, so I started hatching an escape scheme. The woods. Yeah. I can escape to the woods. Good thing I couldn't work the damn lock to get outside.
Eventually he calmed down a little and we all tried watching a movie. I think I was in a coma the entire length of the film and kept hearing someone walking around upstairs while imaging that this was never going to end and I was going to be institutionalized. And I didn't even want a damn Pepsi. All I remember seeing and hearing were prizms of light everywhere and the sound of harps, all while I reminded myself to breath. Would sleep make it all go away? Wait, I might die in my sleep, so that won't work. Maybe I can walk it off. No, I might fall as I really don't know where my legs went. I guess I'll just sit here and hope for the best.
Two hours after it began, it began to end. I started feeling a sense of relief and was semi-in control again. We watched Jan Svankmajer's Alice ("said the Mad Hatter") and tried enjoyed what was left of the trip.
If not for the calm heads of my other two friends I would probably have gone out and done something stupid and would have ended up in prison. I haven't dared doing any drugs since that night, and plan on keeping it that way.