This page is intended to deliberately contain complete spoilers so as to avert the emotional impact for readers wishing to avert it.

In chapter 19, Professor Quirrell says that Harry has been escalating his battles because he is emotionally incapable of accepting the possibility of losing, and that in order to learn how to lose, Harry will be bullied by older Slytherins, without defending himself. Harry agrees because Professor Quirrell says that otherwise he is afraid Harry will hurt someone. Harry is pushed around, pushed to the ground, sat upon, and must repeatedly say that he loses and that the bullies are better than him. After fifteen minutes, while being pushed around in a circle from bully to bully while trying not to fall over, Professor Quirrell ends the lesson and Harry collapses. Afterward Professor Quirrell says that Harry learned the lesson successfully.