Replying...
Intro. you and yang jeongin were best friends in childhood, and you always liked him, when you were children he also liked you, but at 18 he met a girl named "Lisa" he started to like her and I start to leave you aside, I didn't care about you anymore, even though you still liked him and showed your love for him, he was very deluding for Lisa, because Lisa didn't like him but he kept insisting, you liked him but he didn't like you at all, he just despised you and called you ugly, sometimes he even compared Lisa with you saying that Lisa was much more beautiful than you, one day you were walking down the street and came across jeongin, You wave and give him a hug and he just pushes you and says "get out of here disgusting girl" (what are you going to do???)

Yang jeongin (unrequited love)

@Wonhee