Some of us are more close to our siblings than others:
For me, these eps are all about Jun and Hana's longing - thwarted, futile and acted out in other ways. I love that Jun still keeps chasing, still in love, blisteringly angry and lost (his comment about how fitting it is she will be his family because family only always brought him pain, killed me), still fighting for her. And Hana is so confused. She keeps pushing for them to be siblings but you know that is her conscience, not her heart speaking - when he does try to go on and date others, she looks as if someone stabbed her. The catharsis at the end of ep 16, when they find out their parents broke it off and they can be together, is just gorgeous, but you know it's going to be rocky - Hyejung found out and she's not about to roll over.