hahahhaha I know exactly what you mean, getting spun just thinking about it.
When I started out, the first time my friends got crank and I smoked it with them. At first I thought all crank was shitty but later on I learned that there's shooter's crank, smoker's crank, shooter's crystal, smoker's crystal, etc. I've done formeldahyde dope, I've heard of people doing sugar dope but never wanted to try it because it's not meant for shooting.
I've steamed down a resinated roker, let it crack back in the bowl, added water to it and shot that on multiple occasions. It gets you high but it doesn't really have legs. I've also taken dried-up cottons that were coated with shit, dropped water on them and did that.
I also know exactly what you mean with getting addicted to the process itself. If I drew back a load of 20CC's of pure water and did it right now it would get me high just through the brain's memory of undergoing the real process so many times. Just the exhileration of the needle going in and drawing back blood gets me off.