In other sad dramas, characters die and bad things happen to them, but this drama was one of the saddest dramas I've ever seen, even though it had a very slow process and nothing particularly sad happened during it. Because the characters, although they are calm on the outside, but they carry the deep pain of their past. They have terrible memories that were related to their past but directly affected their today lives.
One of the strong points of this series was its strong characterization, even side characters such as Moon Soo's mom and dad, and grandma, and even Kang Do's friend.

It was very rich and deep, and the author was surely a very understanding person. It was one of the best drama of my life and I highly recommend it.