Chanyong was being misunderstood and he's determined to get his Minwoo back! 

Of course, being April Fool's Day, Minwoo didn't believe him at first. But Chanyong followed him around, pestering. Between classes. During lunchbreak. Even on the way home. Minwoo thought the joke was over once he'd shut the door in Chanyong's face. A joke it must have been, because he seemed to have left Minwoo alone after that.