wow I was so surprised to read this comments, I thought everyone liked Hwas (he is ML protogonist) and didn't liked SML.
I wouldn't say Hwan was villain, no one is villain or absolutely good in this drama and that is the best part of it, it's realistic, real life feel, real and raw emotions, real human characters and relationships.in other drama many actions from these characters could be defined as "bad" (Hwan being in love with sis in law, also Seo jin's actions, or their mother's actions) but here we see real humans with their weakens, desires and fears and everything is natural.
3 of them, main characters are selfish sometimes and also selfless, I liked that Seo Jin (Ha Seok Jin) said himself that he is selfish... and so what? aren't most of the people selfish? I kind of shiped him more with FL but I loved every character and every relationship.
same is Hwan, he was selfless so many times but wanted to be selfish too, his monologue before wedding was so emotional, I will never forget it.