The story of Kang Dan-i and Cha Eun-Ho fulfilled me. I used to be a avid reader (not as much anymore), and this just warmed my heart. In the first half of the series, we get to see how much Eun-Ho loves Dan-i. The little remarks and the jealousy (which she is oblivious to) at the beginning just made it feel real. (Eun-Ho was jealous of Mr. Umbrella AKA Ji Seo Joon).
The second half broke my heart and put it back together, from when Dan-i quit to when she was hired again. Her journey is a bonus book in my heart. Plus the line, "The moon is beautiful." Everything has more meaning. Especially at the end of the episodes when they had little recaps or moments written down. This was such a gift. I would definitely rewatch it.