Worst tasting? NBOMe blotters have a vileness like nothing else. Mushrooms taste worse then dirt. DOC has a pretty foul taste, but since the needed dose is so small & it hits slower I'll keep subbing it instead of parachuting.
MDA parachute opened a little before I swallowed once, that was atrocious. Wine, especially red, I literally cannot stand. Even the smell makes me mildly sick. Any cough syrup too, don't think I could bear the taste of medicinal doses even at this point.
As for worst smelling, DMT & DPT. Yet I actually don't mind smoking them, and my lungs have adapted to smoked (vaped) tryptamines quite well. I choke more just smoking fat bowls of weed then blasting off oddly enough!
Best taste would be any hash or hash oil, as well as quality beer. Best smelling, any cannabis. Some that aren't as bad as their reputations, kratom, I can straight up chug kratom tea (THE way to prepare it) at this point, not a great taste but not bad. Poppy seed tea does in fact taste awful, but it's not nearly as bad as often made out to be.
Oh yeah, lastly, the worst tasting of all, morning glory seeds! Haven't done them in like 2 years but the thought of that taste, which I'll remember forever, is enough to make me shudder.