So I started watching this drama a few days ago after 11 of the total 12 episodes of season 1 had already been released. BIG MISTAKE. Each episode of this drama is almost 1 and a half hour long. And it's worth every second so I couldn't help but binge watch. I was sleep deprived and exhilarated at the same time.
Hospital Playlist has a little of everything. It will literally cheer you up. The inter-relationship shown between different characters is perfect. Every actor no matter how minor their role was, portrayed their characters perfectly. Even though I didn't understand half the medical talk in the series I still enjoyed it.
The chemistry between the 5 main characters was off the charts.

Song-Hwa was like the fairy god-mother of the group. All the others seem to come to her for advice. She could do everything perfectly. All the mothers also loved her (Seok Hyeong and Jeong won's mothers trying to set them up with her was very funny). She was described as the emotional pillar of the group which was spot on but she herself, at times, seemed to require some emotional support. (which is why I shipped her with Ik-jun rather than with Chi-hong. While she took care and guided Chi-hong like she did with others, Ik-jun seemed to take care of her instead. He was just as much her support as she was his)

Ik-Jun was the comedian of the group. When things got too serious he would break the tension with some humor. He also had a sociable and likable personality and got along well with everybody. He could also be responsible and serious at times which showed mainly during his interactions with U-ju, Ik-sun and the other 4. He poked his nose in everyone's business and would help them out.

Jun-Wan was the moody and silent helper type of the group. He was a great doctor although with a prickly personality. He also didn't explain his actions to others. He would do good and endearing things but never take credit. He and Song-hwa had a sibling type relationship (If the writers would have suddenly said that they were siblings I would have totally believed it). His and Ik-jun's friendship was the most entertaining to watch (since one was secretive and the other nosy). His relationship with Ik-sun was surprising but turned out good. His character had the most development in the series (from playboy to committed man and from insensitive to understanding) .

Seok-Hyeong was the anti-social/introvert of the group (The ones who don't make friends but are adopted into the group). Despite his problems with inter-personal relationships, he was a great doctor, responsible, thoughful and generally nice. I had really wish that he had atleast given Min-ah a chance instead of flat out rejecting her (I was rooting for her since her feelings for him went from dislike to respect to resentment to finally liking him which was great development).

Jeong-Won was the adorable baby of the group. He was empathetic, sensitive and friendly. His character also developed so much. I feel like every person that watched this series was rooting for him and Gyeo-wool to get together. ( I literally hid behind a pillow when she confessed her feelings and then pumped my fists in the air when they kissed. Most.Satisfying.Kiss.Ever.)
Gyeo-wool's character also went from robot doctor to become more understanding towards others feelings.
Rosa and Jong-su's friendship and banter was hilarious and just perfect.
Seok-min and Sun-bin's pairing was also very sweet.
Jae-hak's growth from fumbling amateur to a responsible doctor was good to see. His and Jun-wan's relationship as mentor-mentee helped .oth of them grow.
The twins Hong-doo and Yun-bok as well as U-ju added so much cuteness and fun to the show.
The music was great. It didn't really hit the same for me since I am not korean but it was still fun (since most of the songs were old I feel like they were supposed to induce the feeling of nostalgia). The concept of the band was also good and unique.
In conclusion I would recommend this drama to everybody whether you like the genre or not .