So I believe everything is perfect about the show. From the production to the music, acting, cinematography, characters, art design, story (well almost). As other reviewers have already mentioned how this is a character-driven drama and mostly focuses on the healing of the 3 main characters among other patients in the hospital.

There are a lot of things I loved about this drama. I loved the focus on mental health awareness. There were a lot of side characters whose story was really beautiful and it made me tear up a bit. The show respects all its patients and takes great care of them. Some of them were healed and some of them obviously were in progress.

I loved the writing aspect of the show. The storybook concept was beautifully crafted with the inner lives of our leads and other patients, so it gives a second layer of storytelling to help us understand their struggles. The art again was very well done.
I loved the acting in the show. the actor who played Sang Tae was amazing. Our main romantic leads also had amazing chemistry and the female lead was a revelation to me. I usually don't like KSH, but I really liked him here.

Now let's talk about characters and their development. The best development was obviously among the 2 brothers. their relationship really evolved during the show to not only make them less co-dependent but to value each other more as people and as family. I loved Ju-Ri's mom and other side characters specially Jae-Su Gang Tae's friend and MY's colleagues. Even Ju-Ri and the manager's brief romance was cute. I was a little disappointed was with our female lead whom I found kind of irritating. Because of her personality disorder, every time she would do something chaotic, the viewers will have to rationalize that behavior (its clever writing to excuse her behavior though). Also, I wanted to understand how her APD works but that plot was soon forgotten in the later episodes. I predicted her mom plot in EP-10 itself, but that itself was extremely undercooked.

I totally understand the writer's perspective that MY's craziness was required for Gang Tae to help him release his pent-up frustration and she might be good for him overall. but as a viewer watching MY harass Gang-Tae was uncomfortable to watch. It is why I've left many dramas like Oh My Ghostess.

So while everything was amazing on paper, I seriously could get myself to care about any of the main characters. The plot in itself was extremely draggy, and I myself wanted to drop the show many times. Even the romance could not get me hooked as I was not invested in the romance. Also, like another reviewer mentioned I have a low tolerance for self-loathing and pity so while it can a great drama for others, for me it was meh. But yes I completely appreciate the team behind the show.