What metaphor do both Dr. Thurmer and Spencer use in order to try to convince Holden that he needs to change his outlook on school and life in general? How does Holden react to this metaphor?

Mr. Spencer sits in a ratty old bathrobe and asks Holden to sit down. Holden tells him that Dr. Thurmer lectured him about how “life is a game” and that one should “play it according to the rules”—just before he expelled him. Mr. Spencer replies that Dr. Thurmer was correct, but Holden holds to the thought that life is only a game if you are on the right side.