I originally gave this book 3 stars - I didn't love it, but it wasn't horrible - but as time has passed and people ask, "Have you read Girl on a Train!?" I always answer with an unenthusiastic "yes" and start thinking about how disappointing it was. So I've downgraded it to 2 stars. 
 This book taught me one very important lesson: never believe it when a book is marketed as "the next [insert awesome popular title here]." The publishers just want your money. I read Girl on a Train for a book club, but would have picked it up eventually anyway since it was being compared to Gone Girl. I was disappointed to discover that it didn't even come close to Gillian Flynn's thrilling mystery. I wonder if I would have liked it better had I not gone into it thinking it was the "next Gone Girl." My expectations would have been different, and maybe I could have appreciated it more. 
 Once I was finished, I felt many things. I was confused - most of our book club discussion was about the therapist (the storyline involving him, Tom, and Megan was poorly executed). I was baffled - why is everyone freaking out about this book? It wasn't horrible, but it wasn't amazing either. I was disappointed - I called who the killer was pretty early on, and it kind of ruined the rest of the book for me. Also, the three leading women weren't very likable, so I didn't feel invested in what happened to them, which made it very hard to get sucked into the book. Lastly, I felt cheated - I had been expecting a shocking, clever, mind-twisting thriller, but instead found myself excited for it to just be over.