why this is so disappointing

the way the story developed made it SEEM like MC would end up with Junseo: MC in love with Karam from the start bc Karam is a generic popular nice boy (means it won't last and is just a plot device), Junseo ends up getting closer to and falling in love with MC trying to help him with his love (generic romance plot), Junseo having way more character development and depth than Karam (to make us root for Junseo). there's probably more but it's been so long since I read it. but this is why the ending is so unsatisifying and disappointing.

it's like watching a master baker make you homemade cookies. you can tell when they make them that they're going to be warm and delicious and the best cookies you've ever had. and then at the end they put it in the oven but never turn it on. and they just hand you a cabbage.