No one intentionally makes bad decisions. Yet we make them all the time. In fact, some of the worst disasters in recent history--the collapse of major investment banks, the global financial meltdown--were the result of seemingly reasonable decisions made by a lot of smart people. How does this happen? Michael Mauboussin, author of "Think Twice: Harnessing the Power of Counterintuition," explores the answers to these questions in this session, a plenary at the Center for Effective Philanthropy's 2011 conference.