Choi Seungcheol who's very firm and a person who makes troubles or fights is very gentle and careful when it comes to his roommate Yoon Jeonghan who's very sensitive, soft hearted and soft spoken.

Example:

When Seungcheol texted someone else: "Hey, i heard you were talking sh!t about me earlier. Meet me in the park or i will beat you up"

When Seungcheol texted Jeonghan: "Hey, i can hear you crying. If you want to talk to me i'm always here :)"