In drugs, I've found limited but definite utility. Occasionally I use drugs because they make me feel awesome. Alcohol is the drug of choice for this (mostly due to availability, legality, and it is easy to moderate your intake, although there are better drugs if these aren't concerns).
The most useful drugs I've found are the ones that make you uncomfortable with some aspect of yourself. I appreciate having my shortcomings exposed to me. Of course, you don't *need* drugs for this kind of thing. They are a good kick in the pants though, if you aren't inclined to spontaneous soul-searching.
Also, some drugs have inspired me to take an active interest in things that otherwise had been really boring to me (auto mechanics, racing, history, physics/maths, music theory). There is some utility in that.
1. Opioids and various pain killers
The rest are either a waste of time or an amusing experience that does not bear repeating.