This is a Korean remake of a Korean show from only 4 years earlier. I watched it because I like the actors, but got bored because it feels like a word-for-word clone of the original. I plowed on through this first season, but dropped it early in the second. My interest just couldn't be sustained in the interim.
All of the actors do a good job. In particular, Jung Chae Yeon's ability to channel Park So Dam is uncanny! I'm seriously impressed. The problem is that, like the screenwriters (assuming they didn't just reuse the original scripts), none of them brought anything new to these already familiar characters. I really felt like I was watching Because It's The First Time itself all over again. And while I liked that show, it held no rewatch appeal for me.
I didn't even notice the music, so I guess it did it's job.
Show is not bad, Show is just unnecessary. There is nothing particularly wrong with it outside of the fact that it's existence is superfluous. But if you like it, don't bother going back to watch the original; you'll just have the same deja-vu that I had but in reverse.