The beauty of books is that you can read and feel inter thoughts of the main character. For example the relationships that are formed or how they are there. Drew, Molly and Peter are the best of friends in the novels. I also see a lot of scenes out of order. What would have been nice is to see the outcome of the scenes that transformed tris. Like when she beat Molly in the fight because of what she said in the interview with Erudite or when Christina took the flag from Tris in capture the flag. How Al struggled and her relationship with him. Tori was never rude to Tris. When her mom visits on Family day. How Peter took out Edward. How uriuh invites tris to a secret initiation with dauntless born. These are all moments of what shapes tris to begin with and her relationships with these individuals.
However I will give some credit as I watched the movies before I read the books and I fell in love with the story enough to read the books. Now I feel like a nasty critic. In my personal opinion the movies aren’t long enough and I wish I got to see this story unfold how it was meant to and this series would have become successful and would have been able to be finished.