I'll keep it short and simple: They should have ended the series in season 1 adding just 2-4 episodes totaling 22/24 episodes.

There were good things in season 2 but there were more things that made the drama bad than good. The direction of the story completely went south and one bad decision led to another. They did a great job with season 1 and should have just kept using the same formula instead of being ambiguous. The writers definitely had a hard time choosing between one or the other, so they decided to create a story of in-betweens. They should have just committed to one direction of a possible story instead of trying to please both sides.

Season 2 kinda felt like a mess and the final scenes were lackluster and unsatisfactory, but I wouldn't say that the drama was completely bad. Ultimately, season 1 was an absolute masterpiece, while season 2 needs to be watched just to achieve closure from the drama -- unfortunately.

Side note: I love the main cast of both seasons to death. I wish nothing more than their success in future dramas <3