I am thinking that smile code might be for Gu Yi not for Dai Wen. Gu Yi isn't really a happy person but a type of broken person who hides her pain through her smile. I am that kind of person but I am not sure if that is the same path Gu Yi is. A lot of people think that I am just a happy guy but little they know I am crying in silence almost all of the time and dramas, anime, novels has been my source of happiness and escape from my problems.
I don't know what's on someone's mind that the drama isnt even at the middle yet they put low score. This is more than just a love story for me but rather an emotional and something to learn from.
Looking at the comments I can tell a lot of people don't understand the story at all but instead they focused on things that isn't really the main topic or the whole thought of the story