New graduates walk out of the chapel after their commencement at Princeton University in Princeton, New Jersey, U.S., on Sunday, June 2, 2013. Ben S. Bernanke, chairman of the U.S. Federal Reserve, returning to the Princeton University campus where he taught economics for 17 years, offered graduating seniors often humorous advice on subjects ranging from love and success to money and politics in a speech that quoted St. Luke, Lily Tomlin and Forrest Gump. Photographer: Michael Nagle/Bloomberg via Getty Images