According to Jack, how does his mother teach him the value of competition in the book, Jack: Straight from the Gut?

Jack's mother teaches him the value of competition when she appears in his high school locker room to scold him. Jack was mad about losing a hockey game and threw his stick down on the ice, storming away to the locker room. His mother tells him he has no business playing if he does not know how to lose as well as how to win.