At the beginning of the year, word emerged that David Fincher’s “Gone Girl,” based on the best-seller by Gillian Flynn, would throw fans for a loop by switching up the ending. “Ben [Affleck] was so shocked by it. He would say, ‘This is a whole new third act! She literally threw that third act out and started from scratch,’” the author herself told EW at the time. But hitting a Reddit AMA today, she tempered her comments a bit.