For some people, Shin Yu Na is one of those people who would never lose a smile; however, for Yu Na herself, she's someone who would easily break down. 

She was fine with having to hide everything behind a mask she had built and wore for ten years already. She's fine to tell everyone to never hurt themselves because it's only useless even if she was doing it herself. She was fine with being the one to ask everyone if they're okay even if she's broken inside and want someone to embrace her. She was fine living like that; living like that would at least make her smile. That is until Kim Taehyung came into the picture.