After I made a resolution to watch all the dramas I wanted to but I didn't have the time for, I picked up this one. And wow I found I diamond. I feel as though if I say too much I will give out too many spoilers so I'll try my best in writing this review without giving away much!
I only give a ten for the dramas I think are the ones that completely caught me off guard or had something unique and new in them that separated them from the rest. This drama was one of them. I had mixed feelings when I started this show mainly because this person(ML) had some problem medically and also because the title and the synopsis did not give much info about the drama and I personally felt it would be something like most amnesia dramas filled with twists and turns. But to my surprise it was something I had enjoyed for the first time especially because of the acting rather than the story. Though I know I am watching it rather late and the rating is rather too personal, but this drama deserves it from what I watched and experienced.

The story, though I had guessed much what would happen and how it would flow from the first episode, it had something I had not expected in each episode and didn't drift off topic like some dramas. I quite appreciated it having a direction and thought from beginning to end. It was of the first of this kind from what I watched mainly because I avoided anything related to amnesia and DID's but on the contrary found out I loved this drama and wanted more of the same kind. It was slightly addicting due to the fact that is shown that the ML's alternate personalities would disappear or go away, and I couldn't put down my laptop until I found out how they were gonna cure him(ML). I slightly felt reluctant to say goodbye to them as I liked each and every personality and fell in love with each of them.
I loved how the actor(Ji Sung) brought out various sides within one person and each personality he acted was unique and very well performed. I was so satisfied with his performance that at moments I felt as if it all was true and that he too experienced it(DID) as well. The acting was so real-like that he was able to win a fan like me(who rarely focuses on acting and mainly listens only to the story). From what I saw this drama was also a very good platform to him to bring out his outstanding acting. From some DID related dramas I later watched, I noticed it is quite hard to perform such kind of topics and was very surprised to actually find Ji Sung performing it very life like.

Dissociative identity disorder is sometimes a very sensitive topic among people as people have different opinions and views on each. Portraying a drama related to or focusing on such a sensitive topic was another thing I paid attention on as bringing out the importance and consequences of DID along with not being opinionated or focusing on one's own views and experiences through out the show was a very difficult thing. There was enough comedy to not make it a melo and also enough seriousness and importance shown on DID that made it easier to convey the message the director and writer wanted to convey.
And I'm not gonna say anything more about the romance, it was just right not too much and not too less, at moments it even made me feel as though the FL will fall in love with one of the ML's personalities and it will give one of those star-crossed lovers vibe. But this shows the drama achieved its motive.

Overall I would definitely recommend and rewatch it! It was nice and an enjoyable drama is to be shared. But this is totally according to and depends on peoples preferences. From what I know about myself it was one of those dramas I would never watch but watched it because I had the time and boredom but actually on the contrary enjoyed it so much I wanted to share it and watch it again sometime later. Maybe you too would feel like me. Comment if you too enjoyed it!