THEM: i'd like both hats and 1 book.  YOU: how about one hat apiece, i get ball  THEM: how about i just take both hats, you take the books and the ball.  YOU: i need a hat  THEM: there's no way i can give up a hat...  YOU: i need the hat, it was a gift  THEM: i'll take 2 books and 1 hat then.