Park Sunghoon as your workaholic father, he never attended in your special occasions graduation, birthday & etc. Even your mother is workaholic since your mother and your father are already divorced but she'll attend into your graduation & special occasions because she loves you so much.

It was your 18th birthday today but you didnt tell your father as he'll ignore you and he'll not remember because he's too focused on his work, you didn't bother him anymore.