As the queenka of her high school, Sunyoung is heralded as veritably beautiful. She has long dark hair, bright eyes, and fair skin. In many appearances, she is often seen with a very attractive figure, having wide hips and a sizeable bust.
As a mother in her 30's, Sunyoung does not look much different, aside from the notable bags under her eyes.
Similar to Daegwang, Sunyoung is marked by her intense dislike for her spouse. Raising their child Joonsu forces her to stay home for most of her maternal life, only for her husband to come home late at night, drunk and desiring sex. She is disgusted not only be his distasteful advances on her when she tries to sleep, but also by his frequent masturbatory sessions, especially while Joonsu is still awake. Not only that, but she is severely disappointed in Daegwang's meager salary for all the time he spends at work. This culminates in her regretting having married Daegwang in the first place, resulting in their time slip.
After time-slipping, Sunyoung becomes very opportunistic with her new lease on life, attempting to date Byoungjin once she knows that he would become a very rich man. Her successful attempts at starting relationships allows her to brag and show off against Daegwang, using both her experience as a truly older woman and her charms to easily attract other men.
However, not too long after time-slipping, Sunyoung begins remembering all the happy memories of not only her and Daegwang, but especially of their son Joonsu, whom ceased to exist when they time-slipped. While she initially sets the goal for herself to forget everything about her previous life using the "one-night stand" rule of time-slippers, she inevitably breaks down crying on multiple occasions whenever a memory of Joonsu surfaces, showing how much she loved her son. Eventually, this leads her to almost raping Daegwang as a mentally-lapsed attempt at getting Joonsu back, though she comes back to her senses before anything serious could be done. Rarely she will react to Daegwang's action with anything but disdain, but there are a handful of scenarios where she learns of his indirect attempts at giving her a better life, causing her to poorly stifle feelings of gratefulness and flattery.