It's got to be 5-MeO-DiPT, from what i remember it was completely useless and disgusting, with nervous, uncomfortable feeling with no depth or anything valuable. I tried it few times many years ago and every time under it's influence felt like just a few wasted hours. Probably tells something about it's shittiness that i can't even remember how to descripe it properly.
Amanita muscaria (also many years ago), made me just vomit like crazy and feel feverish. For added bonus it left me with the most undescribably disgusting taste in my mouth, almost making me vomit everytime i remembered that taste for quite awhile. Didn't obviously dry it long enough before consumption. I have heard that if properly prepared they can give quite an interesting experience but my stomach is probably too traumatized from it to even consider trying it again at least for few decades.
Morning glory seeds gave me one of the worst body loads ever too, but they at least had some, almost too much mentally challenging, depth to them on the one occasion i tried them.
For me, Ayahuasca....That shit tormemted me for hours....Sick stuff...
Aya is very hard on the body too, but i think that's part of the "purifying" process (well the point of the whole "Purge" can be argued tho). It's the one psychedelic i consider to have absolutely no recreational value and being purely a very serious shamanistic/therapeutic tool. However I have only used it with syrian rue and moclobemide, not with caapi as the real ayahuasca is supposed to be.
I don't get the Salvia hate at all, it produces totally unique journeys imo. And shrooms are my favourite psychedelic no doubt.
Would love to try DPT someday!