Freon is a chemical CLASS, not a drug.
Dramamine - Nasty buzz that never ends.
DXM - I felt dirty, and ripped off. First time I found out that DXM was being sold as MDMA. Pissed me off royally. From there I went into uber bad trip mode.
PMA - Discovered how bad that stuff was first hand. Bought two of the pink superman's. One was real MDMA, and the other was PMA. I was slightly pissed in an evil demonic tripping way. I'm one of the lucky ones that didn't get killed from that crap too.

Or maybe unlucky.
Nutmeg - Never got anything off it.
Myscaline(sp?) - It never ended. I like to trip for long time's, but I couldn't even relax for like 24 hours. I started to get very tired, and sore. I also had to go to work while on it. Didn't make me a happy camper, but there where some hot chicks at work that day, and I got to see some action.
Never gotten the chance to try any of those weird 2c-** ones everyone, but me, can seem to get. Dramamine is at the top of the list though. Nasty crap. Evil buzzing head feeling. I lost almost three days on that crap.