There are some lessons they do not teach you in business school. Sometimes you just have to live and learn. For business leaders—even the most successful ones—leadership itself presents daily challenges with consequences that can affect many people. Often the right path is not obvious or the easiest solution, but the lessons learned are invaluable and the experience is a rite of passage. We asked 11 members of YPO, “What is the most important leadership lesson you have learned?” for examples.