THEM: hello i would like the ball, the hat, and 2 books.  YOU: no. how about i get the ball and you get the rest.  THEM: no. i will take the ball and 1 book.  YOU: no it has to be even. i'll take the ball and you get everything else. that seems fair.  THEM: i will take the ball and no books.  YOU: you must be seeing different values than me. i want the ball.  THEM: then it seems we have reached an impasse.