Carleton Gajdusek died at the age of 85. One of the smartest people I've ever met (Nobel Laureate, spoke >14 languages, could teach you more about science in one afternoon than most people learn in five years), and who used that intelligence to save a lot of lives and investigate a lot of very strange diseases. He was also a notoriously difficult person with unacceptable sexual practices.
This combination of facts about his life present you with a moral truth: great good does not erase great harm, nor do our mistakes in life cancel out our virtues. It's an unexpected finding, this ambivalence; we would hope that good or evil deeds might take root and bear further fruit, that the people we meet in this life could be easily sorted, that we ourselves could wake to find our consciences as clean as we found them, that the meaning of actions does not change in memory. This is not the case. We are all of us, many people within.
Who do you meet, in the 1,000,000+ words of Gajdusek's journals? Who do you meet on the street every day? How do you know?