Most times he won't eat things that he would normally like, if they've been polluted first by foods he doesn't like.
He likes mac & cheese, but we always put peas in it. He has to eat the peas if he wants the mac & cheese, but he pulls every last damn pea out (they're shell pasta, so guess where all the peas go), eats the pasta, then gags down the peas because he has to. I've seen him take a good hour to eat a portion.