I agree that this drama is very underrated. I laughed, smiled, cried, and empathised with the characters in the story. They were well-written and modeled after cats and dogs. The main couple were charming as well as the second couple. If in other dramas, even in Chinese dramas, you'd often feel like skipping the story of the second couple because they seem like fillers, but the second couple in this series was adorable. Both couples are like dogs and cats which are natural enemies but here, they fell in love. Even the parents in this drama were funny. All of them sorted out their differences and misunderstandings, some of which were thanks to our stray turned domesticated cat-boy, Hong-Jo. The actors were also exceptional and their portrayals will really make you see their cat/dog characteristics. If you're hesitating to watch this drama, give it a go and see for yourself. Maybe you won't look at your pet in the same way again after watching.
P. S. It's an (open) happy ending. I'd like to believe the webtoon Sol-A wrote and her story with Hong-Jo had a happy ending after all the waiting since there's not much explanation in the end.