Too little back story, my patner couldn't understand why things happened because there was no setup. And why did the storyline have to be told in countless flashback/flashforward scenes? The book had the 6 characters stories told twice each. If I had not have read the book I probably would have enjoyed the movie more, but my partner who did not read the book still had too many questions about how things were connected, The significance of later things because the back stories just weren't well enough written.