Clearly, the most of the viewers have watched this whole show while being biased towards one of the male leads.
Whenever a love triangle is strong, the rating of the series get heavily affected.

Watching from a neutral point of view, without liking one ML over the other, the story was quite well executed. I loved the OST, the production was obviously very high as Netflix was involved, the animations were superb.

The female lead because of the her horrible past, was quite selfish in some of her choices as clearly portrayed at the end of Season 2 as she herself comes to realize how selfish her choices were.

Unfortunately the ones to suffer due to female lead's choices were the two male leads. Considering that Sun-Oh fell for JJ knowing how much of a crush his best friend had on her and Hye-yeong also was ultimately unable to keep the childhood promise he made to Sun-Oh. The whole thing is a a bit Karmic and balances everything out.

With everyone having their share of trouble and ultimately finding some kind of happiness in the end.

This is only worth watching if you are able to watch it without tilting towards one of the male leads, If you do then you will be very angry the way the story goes and how it ends.