I enjoyed the process of reading this. Maybe because so much of it drove me NUTS I couldn't stop. I had the thought, "THIS WOULD NEVER HAPPEN" every 5 minutes or so. The notes I took in my phone: 
 I hate Nina. Why is she SO COOL and bitchy and why did she go to the bachelorette party? 
 Everyone sounds like they are 60 
 Of course they're drinking. Do I smell an unreliable narrator? Dumb tool to stir suspicion. 
 It sounds like this was written in 90 minutes in a writing workshop. 
 Everything is overexplained 
 Why are they torturing the narrator so much? This would not happen. 
 But I was on pins and needles until the end, and I did not suspect the ending. So it was much better than The Girl on the Train. Actually quite fun to read.