I believe this book is good if you are looking for that friends-to-lovers trope, but there did not seem to be much in terms of plot or characterization. I personally found Poppy to be quite insufferable and frankly, immature. Most of the dialogue felt scripted and sometimes cringe, as it was hard to picture people actually talking like this.
I feel like Alex's character was not expanded on, but I guess that is to be expected when you have a first-person narrator who can only tell things from their point of view.
The thing that got me the most about this book was the talk of the Croatia trip from two summers ago; there was this huge buildup to it from the beginning, only for it to be the most predictable and anticlimactic turn of events imaginable. That chapter also seemed a lot shorter than all other chapters, so there was hardly any explanation as to why that summer trip caused such a dent in Poppy and Alex's friendship. Plus, it seems stupid that they never talked it out during those two years after all their years of being friends and the strong bond they have with one another.