The initial episodes of the first season were reasonably good, but the show’s decision to focus on a school environment brought about numerous issues. It felt like every overused high school storyline was exaggerated with awkwardness, resulting in something incredibly cheesy. Jason proved to be the weakest element—the character, the actor's performance, and the writing behind him—which negatively impacted his relationship with his romantic interest. The plot’s progression seemed foreseeable from the beginning, but it deteriorated considerably during the final third of the season. The narrative felt stuck in place, the characters became disjointed, and there were extended scenes featuring minor roles that added nothing. Sam Dong's appearances were noticeably reduced, and Pil Sook and Jason were separated from the rest of the cast, with minimal interaction among them. This all contributed to a disappointing final episode and an uninspired conclusion. Despite these shortcomings, it managed to be somewhat engaging. The second season was clearly inferior in every aspect; it’s simply not as good. The filler scenes that existed previously became poorly executed musical numbers, primarily featuring Korean songs, unlike the first season which incorporated more international music. There was a lack of chemistry between all the characters and pairings, making them feel forced and lifeless. It also concluded in the same way as the previous season. I got the impression there were more idol group members than experienced actors involved. The change in directors and writers essentially sealed its fate from the start.

Source on TMDB