Potatoes. It's the texture, not the taste. I can't eat them unless they're crisped to the point where you'd need a forensics team to determine that they started out as potatoes.
Also pickles. I'm a "supertaster" and can't stand the taste of vinegar.
Chopped liver. Or probably just liver in general. Dry roasted, served with cottage cheese and chopped cucumbers.
What’s the most widely enjoyed food that you can’t stand, not because of allergies or anything but just because you hate it?