Willpower enables us to get along with others and override impulses that are based on personal short-term interests. It’s the same lesson that Navy SEAL commandos learn during a modern version of Stanley’s ordeals: the famous Hell Week test of continual running, swimming, crawling, and shivering that they must endure on less than five hours’ sleep. At least three-quarters of the men in each SEAL class typically fail to complete training, and the survivors aren’t necessarily the ones with the most muscles, according to Eric Greitens, a SEAL officer.
Aha! So this is the point of harsh military training: not to break down ego, but test willpower.
