I'll be honest, this was on my To Watch list for the longest time. I started the first episode multiple times, didn't like it, and gave up. I picked it up again because I'm hoping for better from seasons 2 & 3.

SPOILERS! SPOILERS! SPOILERS! SPOILERS! SPOILERS! SPOILERS! SPOILERS! SPOILERS! SPOILERS! SPOILERS!
My issues with this drama were many:
1) A lot of overacting for the sake of "drama". I like Han Seok Kyu (though he tends to play this type of character a lot) and Yoo Yeon Seok was fabulous in the Hospital Playlist dramas, but even they over-acted at times. Tons of yelling by everyone.
2) For the most part, pretty unlikeable characters. It starts in episode 1 when Dong Joo says he wants to sleep with Seo Jung and that he likes her. Why? Dr. Kim is pretty insufferable throughout the whole show, constantly yelling and demeaning the staff. Dong Joo - self-serving person with a chip on his shoulder the size of the Grand Canyon.
3) Romance was half-baked and unnecessary. I'm usually into shows for the romance, but I didn't buy the leads as a couple from the very beginning, and I never had any reason to change my opinion. I had no idea why they liked each other, I felt that she was playing him a lot of the times, and I actually got mad during the bonus episode when she was saying that she was "letting him go", thinking that he was going to the US. She was very immature.
4)The storyline was fragmented. Seo Jung has hallucinations and tries to kill herself. She had no business being in the hospital environment until she had gone through extensive therapy. Master Kim demotes her to intern, but she's allowed into surgery. The small hospital was associated with the big main hospital (the staff came from the main hospital to the small hospital) yet no one knew Dr. Kim was there? I mean, you can change your name, but background checks still need to be done.
5) I felt that the medical aspect of the drama fell very short of the mark. There was no getting to know the patients (I refer to Hospital Playlist that shows how to do it right). The patients were just moved through to show the medical team in one crisis after another. Almost EVERY patient needed CPR. I was tempted to make a drinking game of it (and I don't even drink!) - every time someone does chest compressions on someone, take a drink! This show was from 2016 - was the timeline in the show supposed to be different? Because the AIDS storyline was ridiculous for 2016. So much more had been discovered about AIDS and caring for patients. This might be different in Korea, but in the US public hospitals can't refuse to treat people. Then there's the fact that Dr. Kim had a pretty severe wrist injury (which there was no scar from), he could hardly move his hand, but he was insisting on doing surgery. Granted he backed down, but it never would have even come to that. There is a case in an early episode about not treating patients if you don't have privileges there, but this rule is thrown out the window in the last couple of episodes. Then, there was cross-contamination going on in the operating room by handing instruments over open wounds, crossing arms in front of themselves to get instruments, etc. Granted, maybe it only bothered me because I'm in the medical field and it wouldn't have bothered others.
6) The bad guy. and his henchmen. I felt like he was evil for the sake of being evil, I didn't get the motivation. I was also bothered by the fact that he had people in the small hospital as spies for him, and no one seemed to notice.
7) Kim Min Jae as Park Eun Tak was criminally underused. Hopefully that will be rectified in Season 2, if I can manage to get through it.

I realize that I am a minority of one with my feelings on this show, but it's been quite a while since I've watched something that has made me say "that's time I'm never getting back".