Worst thing I've seen: a guy who'd already lost one leg to DVTs stabbing a 23 gauge blue needle into the running, open sore that was his entry point to the femoral vein on the remaining 'good' leg, a leg being treated for, yup, DVTs. Oddly enough the guy was dead not long after. I've seen some sick shit, watched my own sis trying to shoot up in the neck cos she couldn't even hit the femoral any more but that just takes the cake. Made me wanna vomit, could never bring myself to be around the guy again, no way I wanted to see that shit. Too close to home about where my own habit might lead though I like to think I'd have quit long before I ever got that desperate, this guy was just passed all caring.
Worst thing I've done: I dunno but cooking up with water pulled straight out the bowl of a public toilet when I couldn't fill up from a tap and couldn't afford a bottle of water has gotta be up there. Boiled the shit out of it before even putting the H in it but even so, when you find yourself doing shit like that it's time to have a long, hard word with yourself isn't it? Still did it again, good few times.