I hate a great many things, from poor driving to pathetic grammar and spelling. I mean the comment section of a local news website alone... how do these idiots manage to breathe?
But on topic, I'd have to say food. I suppose when I was a kid I used to be picky eater (in the broadest sense):
I never liked steamed vegetables - still don't, but I will eat them. I'd rather have them natural, straight outta the ground. No sense in making shit more complicated and, for that matter, bland tasting (plus, steamed cauliflower smells like old jism left out in the sun).
Tomato soup - never saw the appeal of warm, watered-down ketchup. Now, I'd never make it my first choice, but it doesn't bother me at all.
Mashed potatoes - they just never end and they're bland as shit. It's like eating soaked paper. That's how I felt from the first time I had them, until about age sixteen. Now they're just another side dish.
There's probably more that I just can't remember. Note: I never refused food or 'pouted' - I was never averse to eating a meal when it was served, I just didn't see the appeal in the above. Why the fuck is tomato soup and mashed potatoes considered American pastime cuisine? Peanut butter and jelly, there's another one - how do those flavors mix? How? And how the fuck did everyone afford jelly?
Anyway, the only think I can't truly stomach, (although I've not eaten everything this world has to offer) is cottage cheese. It's difficult, though not impossible, for me to imagine a worse combination of texture and flavor that can hit your tongue. Even though it's a great weapon in your arsenal when getting lean, I cannot stomach it without my body trying to throw it back up.
Now, everything else that I've encountered, I will eat - especially if it's made and served by someone else. Someone actually took the time to think of me and my survival, the necessary consumption of nutrients to keep me alive, and I'm going to say no? I don't think so.