One Spring Night, like much of K-Drama, has many layers. One of the intriguing small stories is that of Lee Jae-in, the younger sister of the show's heroine. In the finale, Jae-in sits by the river with her boyfriend, Park Young-jae. He asks what she is thinking about, and she replies she's thinking about the reason for her return to Korea. He says, "You said you didn't want to study." She answers, "I learned a lesson." He is interested, but she simply offers to clink beer cans with him and looks at him with admiration.
The central reason for her return was that she was stalking a man in France. As that was a crime, she returned home to escape prosecution. On her return, she was plunged into the dramas of her older sisters who were being abused by men who wouldn't leave them alone. The parallels to her own transgressions are profound. She had chased Young-jae at the beginning, seemingly repeating the kind of behavior that had gotten her in trouble in France. This seemed to have sorted itself out as Young-jae realized his own feelings for her, and Jae-in became calmer. It is clear that they share a kind of perspicacity for the doings of those around them. It is a new basis for a relationship, not the obsession that had driven Jae-in before. It is also clear that Young-jae is not the heavy-handed patriarch Jae-in had experienced in her father. Young-jae is kind, loyal, and accepting of others, all qualities Jae-in finds honorable.
I think what Jae-in learned was that the freedom she was longing for was not to be found by abusing others. She couldn't be liberated from the patriarchy by replicating its bad behavior. Rather she needed to find the people who offered breathing room so that she could be herself. In K-Drama, everything is put to use. The quiet scene by the river is perhaps the metaphor that Jae-in has found a man who sees and respects her path and her right to breathe.