The following statement by Sun Tzu applies equally to each of us in our life struggles, just as it does in war.
It is the business of a general to be serene and inscrutable, impartial and self-controlled.
By being serene and self-controlled in any situation, we allow ourselves to think more clearly, assess the situation more completely and make better and wiser decisions.
If we are conflicted, agitated and out of control when faced with our day-to-day problems, issues and challenges, we often make poor choices and worse decisions.
Hence, a good life depends on us being disciplined and self-controlled, especially under stress. This is just another example of how martial arts is life.