When i started watching this film i wondered to myself what part of it should be so sad. The atmosphere was very lighthearted; no problems in sight. But man, i was so extremely wrong.
The reason why i give this movie a 10/10 is because it accomplished to succeed in many aspects. First of all it was very well shot; lightning, camera ... really beautiful. And then there is the the smooth and touching music, which has very nice themes. The essential aspects are the story (or better stories) and characters. Especially the characters are really strong here. The cast did an amazing job in making you feel what they feel. And it was really elegant how this movie was directed. You will never feel a disruption or something similar; very fluent until the very, very sad ending.
I guess people, who like Korean dramas in general will love it. And if you are a first-timer watching Korean dramas: watch it! This is a very nice example here.