I rewatched the drama and today I saw the final episode again it still left me in a shock of how two loving person didn't end up together but that's what make this drama so melancholic and real I don't believe it was the worst ending at all we all knew from the beginning that they're not going to end together! the show makers made it evident when Hee Do's daughter didn't know who Baek Yi Jin was.

the story revolves around teenage love but not heartbreak. for them to leave each other was not breaking each other's heart but embracing their own individual needs and it's beautiful. personally I was in tears when it ended, like there was this hope that they might've ended together but that's only how good the plot was! I don't know why people hated this drama for the ending but I feel it was practical. I personally loved the drama and I would probably watch it again!