It's pretty normal for dramas to have messy storylines, when they are doing live filming, however according to Wikipedia this drama was fully preproduced. For that reason I do not understand why would they even start filming a story written as poorly as this one. There are lots of things that make no sense in regards to the ML's condition, like his daily routine, if I try REALLY hard to understand, then I could maybe accept how he can wake up every day & instead of being confused he just casually reads his later diary entries & then meets ppl & he acts all comfortable with them. Anyway this entire "I have the memories, I just cannot access them, but instinct... " should have been communicated much better with us viewers early on. Even if the fake science behind his illness is all wrong, I could have been okay with all this really, but for a preproduced drama the pacing is all wrong, they made 3-4 episodes worth of filler content that served very little purpose & then we got a super rushed ending that was like 20 minutes long, but could have been an amazing 2 hours. Also the first episode is noticeably lower quality than the other 15 episodes, I was considering dropping the drama 30 minutes in. There were a lot of drama cliches used, I mean A LOT, the meaningless childhood storyline especially stands out.

So why 7 stars & not 4? Well, the romance was cute. The chemistry could have been better, but it was not bad at all and the leads had some pretty awesome moments together. I wanted to watch some fluffy romance & this show did deliver on that front. The villains were just a decoration, they did not do much to make me annoyed. I expected a lot of makjang, but both of the main villains were dealt with effortlessly & none of their attack plots were long, or very distracting. It's nice that the love square was quickly dismantled early on.
The OST was okay, nothing special though.
I don't know about rewatching it, I probably won't!