Underrated for sure.
I loved how the characters developed. No cliche love stories. The sisters did not fall in love with first guy they met. .
I liked that the characters were believable. Their behaviour made sense, despite how much I hated them. Specially in laws, so many times I felt like Cheon youngest sister will change after seeing how her family treated her sister in law and her sister. Though she felt bad, there wasn’t a big change in her. Which I liked.
Liked that they did not show that people change after 1 incident. No one else changed except Cheon Woon Tak and the reason was totally understandable. How amazingly he played his character. He was in control all the time. Not a single scene where he did not shine.
Secretary Goo’s character was slow, patient, never boring.
I also loved that the youngest sister did not give up her dream till the end, and did not show that she succeeded with her dream. It makes sense.. she was young and inexperienced..

Every time I predicted the story, I was proven wrong which is but rare in kdrama..