When she was a toddler in Omaha, her parents called her Mary Sunshine.Warren Buffett's big sister Doris has never lost that quality, despite personal problems that would have soured others on the world. The "retail" philanthropist known as the Sunshine Lady derives such joy from helping others on a one on one basis that emotional abuse by a mother who may have been bipolar, a string of horrific marriages, nearly losing her home after the 1987 stock market crash, two bouts of cancer, and, worst of all, estrangement from her own children, have never hardened her heart. Instead, her own problems have caused empathy for others, evident since childhood, to deepen over the years. She has donated $100 million of her own money, mostly to individuals in trouble through no fault of their own, often taking the time to call them personally to determine the best way to help. At 82, her goal is to give away her entire fortune, which remains substantial despite her generosity and the stock market crash of 2008."She identifies with the underdog," Warren says.Perhaps more important than the material gifts she bestows is her message, resonating through her own example: We can all write our own destiny. We can all maintain nobility, optimism and selflessness in the face of uncertainty and pain. And caring for others more than we do for ourselves is the most rewarding thing in life.