I don't know why, but I absolutely loved this. This was definitely a feel good drama.
There's not a lot of tension or misunderstandings going on, no corporate villain or spiteful mother-in-law, no annoyingly over-persistent second lead... Just regular people going through hardships of life, trying to find answers and do the best they can to move on. It felt almost therapeutic, in a way, watching these people finally accept the reality of things and learn to grow from it.

The story really plays on your emotions, and you feel for every single character. No one is black or white, they're all just different shades of faulty human beings. The AI device doesn't really make sense, but it was never intended to and the story doesn't try to make you understand it; there's no scientific lingo to rationalize its existence - it's a fait accompli, we're now living in a world where this exists, and all that's left is to see how it plays out.

My favourite thing, though, was probably the interactions between the main characters. You can tell they really understand and support each other. They follow each other's pace perfectly, and with no unnecessary jealousy or fighting (a few arguments here and there, but reasonable) their relationship simply flows.

Perfectly wrapped up with a bow in 12 episodes, with gorgeous piano tracks throughout.