It isn't worth it to try and explain why I think that this is one of the best stories ever written and then wonderfully translated onto screen, by an incredible director, cast and everyone involved, honestly there is no way for me to do that. However if you are still not convinced that it is worth the watch, here is my review.
The well informed writing reveals human nature honestly and yet mysteriously. As the story unfolds I have more and more appreciation for writer Jo Yong, bravo. Not only does this story deal with serious themes, these themes are also common in life and is dealt with in a gentle, heartwarming, heartbreaking and often comedic way in which you as the viewer can empathise with every character. And every character has their moment to shine, and shine they do, thanks to the incredible cast. This is not only a drama, but a mystery, a romance, a comedy. It succeeds where very few show do, in that it can make you feel every emotion and then some emotions you don't quite know where to place. And gives you enough meat to think about every theory while you wait for the next episode.
The visual story telling, thanks to director Park Shin Woo is top notch. His transition are seamless. He displays drama, action, romance, suspense and comedy in perfect harmony unique to each one. This drama is the only 'how-to' in visualising storytelling. Every moment is a visual treat from the foreground to the background and every motion in between.
And then the cast. What can I say. The three leads are excellent, beyond excellent actually. I am captivated by every performance, and I truly become immersed into these characters' lives. Bravo once again. These characters are by no means easy to play, with multiple layers, and they are done in ways I don't think I have seen before. Awards all around.
Worth the mention is the music, wardrobe, lighting and well everything. Truly feels as if every person in every department brought their very best and then some.
You simply have to... no, need to watch it.