Heavy opiate or amphetamine users. Honesty, integrity, and morality tend to go out the window pretty quickly. Personally, I blaze a lot, occasionally indulge in psychedelics, tried E once. I have friends that cover the whole spectrum, though. I've met responsible users of just about everything, but have met a lot of trash too. I imagine that would apply to all drug cultures.
It's weird, though. I could smoke an 8th in a day with little effort, but one or two days a week I just wake up not feeling like smoking that day. The way I see it, if I'm high every waking second, is there any real pleasure or experience in being high? It becomes normalcy if you do it too much.