When im eating a fish filet and there are still bones in it. ruins the whole fish for me, just how finding a hair in my food also ruins it for me. Hell, when i'm eating anything soft and then there's something randomly hard inside that's not supposed to be there it makes me cringe. I also hate raw or undercooked onions in general. Cant stand them if they aren't grilled, sauteed, or fried.
Also fat inside meat that tastes good the day its cooked (Usually slow cooked, like a large roast) tends to taste really bad the day after when you reheat it, cause the fat gets all rubbery or hard, making the meat sadly hard to eat. Fat itself doesn't make me cringe if its on the right kind of meat.