In life we choose ... sometimes it may feel like circumstances or other people choose for us. But generally speaking we choose most of the time. We choose our path - looking back on certain decisions we may regret the path we chose. That being said, it doesn't mean it was the wrong one to take. But it is human to reminisce and to think back - and "forward" on what could have been.
Especially when we get a blast from the past. I personally "lost" my childhood friend - in my case it meant she moved out and back to Greece where her and my parents are originally from. In a different timeline (universe?) we would have grown up together ... we would have at least remained best friends ... who knows what else? But it was not meant to be ... and relationships or past "friends" is what this is also about. I feel like my story could be way more interesting than the one on display here, but that's literally a different story (to tell). That does not mean this is a bad one - it's actually a quite decent movie/story to say the least. And great performances.