Elizabeth Gilbert's 2006 memoir, Eat, Pray, Love, sparked a global conversation about what it means to find your calling and fulfill your life's purpose. Her personal transformation -- from a devastating divorce to a yearlong, soul-searching quest around the world -- resonated deeply with millions of readers who could relate to Gilbert's search for authentic happiness. While Gilbert was sharing a lifetime's worth of lessons with a live audience on Oprah's The Life You Want Weekend Tour, one reader asked her an interesting question: What's her greatest regret?