You sit at your desk, reading a book. You came too early, and not long after that, another boy came in, he greeted you and smiled, he sat down next to you, and chatted with you.

Not long after that, Jungkook entered the class, he saw you chatting with another boy, and got even more angry because he sat next to you. He also saw that there was no one else in the class except the two of you, you and the boy. He was upset, he didn't come into your class, he left, you realized his presence and he left, you were confused, you immediately followed him. As long as you follow him, you know that he'll be sulking.