Thankfully, I'm not the one who's stuck having to seek out extreme sour candy.
I've noted, on more than one occasion, that I'm so hypersensitive to the "eye-scream" trope that direct-to-patient ads for AMD treatments delivered by intraocular injection gross me out, to the point where, if faced with a need for such injections (or with cataract surgery) to avoid going blind, I'd likely drop everything else and begin an intensive full-time study of braille.
Now admittedly, sour hard candy is better than a literal poke in the eye, but probably the sourest stuff I normally consume would be sourdough bread, and an occasional plate of chicken piccata.