I really like the series, but admittedly this was my least favorite. The book seemed to rush really quickly at the end, there was no epilogue like the other books had, and there were side stories that didn't seem to wrap up as satisfyingly as they should have.
For example, Megsy. I get that she was supposed to be there to create conflict and romantic tension between Ellie and Adam, but her character seemed... off. She mentions having been in Adam's room the weekend before, but we never get an explanation of why she had been there. She comes up to Ellie during the party and tells her to fuck off, then Ellie finds her passed out in Adam's bedroom. Again, no explanation of how she got there, why Adam didn't drive her home, etc. And then after that, she dropped off the face of the Earth. Didn't have a satisfying ending for her character.
Another example: Adam's big secret about his mom. His explanation for keeping it a secret from Ellie was kind of dumb, in my opinion. They're best friends. They supposedly tell each other everything. When he revealed it, it honestly felt anticlimactic because... well... it just felt so unrealistic. If they're that close, he probably wouldn't have hesitated to tell Ellie all about it as soon as he found out. But, of course, the book needed its angst, so I guess that was one way to have it?
Another example: I would have liked to see more interactions with Adam's mom. She was a big part of Ellie's life; I think it would have made her side story a lot more effective if she and Ellie had shared some moments together (besides the running-into-each-other-at-the-hospital scene). Not to mention that we hardly see much of Ellie's interaction with her parents, aside from her taking her mom to a doctor's appointment.
Overall, it was a good story. Really liked how this was a from-friends-to-lovers novel. Adam and Ellie are perfect for each other, and I'm glad they ended up together. :)