"I want you to hit me as hard as you can." (5.93)
Fight club, which eventually evolves into Project Mayhem, starts with an act of violence. It's like a punch heard 'round the world. After the twist is revealed, it's cool to look back at this scene and see the narrator punching himself in the face. If you want change, eventually you have to stop beating yourself up and do something about it.
I just don't want to die without a few scars. (6.10)
Our narrator doesn't want to be measured by the stuff he owns since, you know, you can't take it with you. But if he can't take his body with him either, those scars will eventually fade, too.
After I said, stop, I could look down and there was a print of half my face in blood on the floor. (6.40)
Fight Club doesn't shy away from blood or gore. Even our narrator is forced to face it head on. Bad puns intended.