One food this bird loves is banana.
The thing is, it makes him rather mental. He sees it and it's got the unique effect of turning him into a fruit predator. His pupils shrink, he'll make some warning calls, but he loves eating it. First time I gave it to him, he grabbed a finger with his claw and just stared at the banana, with his mouth open and tiny evil pupils.
Yet he loves it. This is the only food that turns my parrot into a hawk.