As someone who suffers from depression, the journey can get a little lonely. And, once it stops being lonely, it's very difficult to break my habits and let people in, especially if I don't trust them. I love this drama for two reasons:
a) The realistic portrayal of one of the results of having depression, i.e., need for self reliance. You only trust yourself and no one else. Everyone in your life either gave up on you or treated you with acute absentmindedness and neglect. I see so much of myself in her and my mother in hers.
b) The absolutely beautiful acting by the leads. My goodness, both of them are yearning for love, and are depressed. It's obvious that even though he's "positive", he's suffering from depression. He has separation anxiety and is yearning deeply for love. He doesn't trust others either, however, he loves people and therefore, brings himself to the point wherein he doesn't distrust them. Hyo Rin's absolutely amazing as well. In that, she doesn't play the character in a "crazy" or overstated way. I often see that that's how having depression or anxiety is described, whilst people can have their overheated moments, just like someone without either of those, most of them are calm and quiet, just looking to get through life everyday. I love them both so so much for these roles.

I have ONE problem with this though, and it's only that it was too short. This could've done with another episode or maybe two more, at most. This would have fleshed out the struggles/confrontations that both characters were required to have with themselves, each other, and everyone around them.

Finally, I would love to watch this again, because, GOD, it's kind of life changing. Well done for the story writers, the directors, the music producers, and everyone involved.