Liver and tripe are my main no-no's. And other than that, I'm going to have to go with mayonnaise. I don't understand why everyone is so obsessed with putting mayonnaise on everything! It tastes like something you'd find in a toilet. Oh god, it's vile! Although, I will admit, that a proper tuna sandwich just ain't right without a little bit of it. Other than that, I'm pretty much willing to eat (or at least try) anything.