Food: Probably a century egg. I don't think I ate it "correctly" because I just tried it on its own, and as far as I know you're supposed to eat it with soup or something like that. Either way, it tasted bad and also had a bad texture while in your mouth. The century egg tasted a little bit like rubber and salt, the best way of describing how to eat it would probably be like trying to chew a rubber band that was actually a magical salt rubber band. Also it smelled very interesting, it smelled like a tide pool, a very oceany smell.
Drink wise: Probably a Pu-erh tea, it tasted and smelled like fish. From what I know, I probably brewed it incorrectly, or the leaves in it were dirty or something. I only tried it from a tea bag, from what I know it might not taste like fish if its "proper". I remember reading somewhere that if it is tasting like fish, you should wash the leaves somehow, I never got around to it though. I might be missing the greatest tasting tea in the world for all I know, but I'm not particularly interested in trying it again.
A food that I want to try that I've been told is bad is a Durian, but I've also read that durians are also the greatest thing on Planet Earth. The durian definitely is a food that gets a lot of mixed reviews, but I don't know if I'm ever going to be able to try one as durians are very expensive fruits, I think around $3 a pound depending on where you get them, durians also weigh around 7 pounds or so, so I would be paying around $20 for a fruit that is known to smell bad and I might just end up hating how it tastes.
Weird, both of the things I listed as being the worst I've ever tried were both China.