It's weird the mental clarity that comes with pushing yourself to and past your limits. Right when you think you can't go any further, you push past that wall and that's when you find yourself. It's an amazing feeling. Completely different from the runner's high, more of a clear state of mind. It's like talking with a counselor about your issues and such. You find answers, you find peace, you find god. Life becomes clear. This is why I run.