I actually like the twist after twist scenes, especially the epilogues revealed in each episodes. Every cast are unique and nailed each characters, the production choose the best cast, indeed ? . From undeniably chemistry of soohyun and jiwon to the antagonist (that really hooked me to be stressed and annoyed) is effective to set a rollercoaster emotion to the viewers. Their OST really adds up the tense, It makes you cry, scream, smile, annoyed, sad,... all the OST in this show deserve an award, I reckon. Overall it was the best, the shows realy deserves the ratings. For me, the drama is in the level of DOTS and My Love From The Star.