THEM: i can let you have all the balls in return for the books and hat.  YOU: i would like to have the hat as well  THEM: yes, it is a rather nice hat. if i get the hat and one book you can have everything else.  YOU: the book has no value to me i would prefer the hat  THEM: unfortunately i really need that hat. you can have everything else.  YOU: fine doesnt matter to me.