I'm sure there's at least 6.8 other threads on this, but I searched for them (for 3 seconds) and couldn't find any.
Food you hate, I want reasons too.
1 - Mushrooms. Texture is gross, I also had a bad shroom trip when I was 18 that put me fairly off them
2. Tomato. Texture again, maybe a bit too tangy too. But being a master of controversy, I like tomato puree, ketchup, sundried tomato, tinned tomato.
3. Oysters. Only tried them recently. Initially quite liked them, then had a dozen in a restaurant and was violently ill. When I think of them now, the taste of salty fishy bile is instantly recalled.