I can resume Yuuna as a person who has an obsession with her best friend Dahye. An obsession longing for 10 fucking years. Calling it a crush is misleading. This is a sickness.
And Dahye is a fucking psycho, selfish who doesn't care about Yuuna even though she says it. At the second she knows that Yuuna wouldn't be available for her 7d/7 and 24h/24, she goes insane and plays the victim to earn her back.
But fortunately, they are 2 characters that save this manhua, Jooyoung and Joy. These two deserve so much better than Yuuna. Even the author agrees with that. In the side story, the author blessed us with the best couple, Jooyoung x Joy
Also, Yuuna has a serious problem with alcohol.....All character have problem with it.