Florence Cassassuce, a project coordinator for a Mexican nonprofit group, should have been having the best year of her life. It was 2007, and her work on water purification in Mexico had been credited with curbing the well contamination that leads to waterborne illness. She received widespread recognition for her endeavors, having been named a CNN Hero finalist and World Bank award winner. Although Cassassuce could hardly have achieved more, she did not feel the kind of inner satisfaction that most of us think accompanies such great strides. “I did not want to continue living life like this,” Cassassuce recalls, “searching for external sources of gratification to very temporarily boost my self-esteem.”