The main point of *Can't Hurt Me: Master Your Mind and Defy the Odds* by David Goggins is about harnessing mental toughness, discipline, and self-determination to push beyond perceived limits. Goggins shares his own life story of overcoming extreme adversity—poverty, abuse, racism, obesity, and personal failures—by developing an unbreakable mindset. The book emphasizes that everyone has untapped potential and can achieve greatness by embracing pain, pushing through fear, and setting high standards for themselves. Goggins introduces the concept of the "40% Rule," which suggests that when you feel like quitting, you’re likely only at 40% of your potential.