I heard a lot of bad comments about this drama that's why i didn't feel like watching it for a long time. But because of the cast i finally decided to give it a try and oh boy i am glad i did. This drama is great!
Many people say Park Jae-Eon is a walking red flag and yes he IS, but in my opinion we see a lot of character development for the male and also the female lead. He learns to become a better person through her. While Yu Na Bi learns to become a stronger person through him.
Don't wanna spoil, just go and watch it!