I don't like tomatoes, mushrooms, whipped cream, ketchup, and a number of other things.
A lot of foods I dislike are mixed things. Although I like cheese, pickles, lettuce, I don't like these things mixed. And because I don't like tomatoes or ketchup, my hamburgers are slabs of meat in between two pieces of bread.
And I will happily eat a peanut butter sandwich, or put jelly on toast, but I will not go anywhere near a peanut butter AND jelly sandwich. It's inconceivable.