What do you believe about your capacity?

I'm a big fan of David Goggins. He is a powerhouse. David does things that I imagine no human should be able to do. He is the only person ever to complete Navy Seal, Army Ranger, and Air Force Tactical Air Controller training. He also held the Guinness World Record, doing 4,030 pull-ups in 17 hours. Goggins talks about how when you feel you are finished and physically worn out, your brain is…