Annie Duke is the only person I've ever interviewed who was in my same graduating year at my college...but I didn't know her in college. Annie quit just before completing a PhD that she'd spent years pursuing, in order to become a professional poker player. She hasn't played professionally in about a decade and is STILL the 4th-highest-ranking woman in pro poker earnings. (She was first back in the day.) Annie's new book is entitled "Quit: The Power of Knowing When to Walk Away" and in it she argues that "grit" may be overrated and "quit" may be underrated.