Overrated
-Coke. Why? Too expensive, usually very impure, are there are just better stimulants. Always feels like just a tease.
-Opiates. Why? These just have never given me any euphoria - mainly just nausea and itchiness. I've tried hydocodone, oxycodone, morphine sulfate, hydromorphone, methadone, and heroin, though I've never injected or smoked any. I don't have any interest in it either - for whatever reason I just don't really find them pleasant and it seems I'm quite in the minority here.
-Alcohol. Why? Makes you feel sick, both during and afterwards. Gives you the spins which are one of the worst feelings in the world imo. Makes taking almost any other drug way more dangerous. Fucks up your stomach and basically all your body. And it makes people act like the most intolerable, idiotic versions of themselves. And for some reason everybody loves it so much. Alcohol's ubiquity is frustrating.
Underrated
-DXM. If you can get the pure powder and just weigh and cap your dose, that takes away a lot of the aversion people have for "robo-tripping". And yeah DXM can be a little rough but it is very powerful, bizarre, wonderful drug. At less dissociative doses I would actually describe it as an atypical empathogen. But you can also go quite deep. Very fond memories from this drug.
-Kava. Though I've had a lot of meh kava experiences I've had a few really nice ones. And when I actually went to the kava bar (during happy hour, double shells for the price of 1), and had two double shells I left nice and high, feeling kind of like I had taken a few mg of etizolam (which I also very much enjoy).
-Kanna. It's mild yet at the same time surpisingly effective, and I couldn't believe I had never heard about it before this year.
I also think that weed (especially concentrates), amphetamines, mxe, ketamine, lsd, dmt, mdma, methylone, and 5-mapb are all fucking great but I wouldn't consider them underrated as they're all pretty popular/talked about. I feel like I'm forgetting some good ones at the moment but oh well.