objectively, this isn't a masterpiece... but the chemistry, editing and direction would make you fall in love with it!

Story :
the movie is cut down in various time leaps where you get to see these two characters meet and depart numerous times, because of unavoidable circumstances. even though this could have gotten repetitive and tiring, it doesn't. it's quite believable and it really rises your anticipation for them to finally get together for good. except for the last time they "broke up" but i'll get to it later in the spoilers section.
however, it isn't a unique story. this isn't something that has never been done before, especially in korean cinema. we have seen multiple such stories where a couple makes up and breaks up in span of years. so that's why i wouldn't rate it very high on story.

Acting/Cast :
This. This is what made the movie special. at least, for me. The cast is wonderful. The chemistry between the leads is so amazing you'll giggle along with their cute moments, their shy glances and their subtle and slow advances. It's so beautiful to watch and it's so well done. They feel so natural that you wouldn't for a second think you're watching two actors act.
shout out to their first kiss (if you can even call it that lmao) — it was SOOO PRECIOUS!
jung hae in is such a comfort for eyes. and, no i'm not talking about his visuals. any drama, any scene, any character he is in, you just get enchanted by his performance. and i believe he has literally mastered the art of the sub-genre that is 'slow burns'. his performance was beautiful, but then i expect nothing less from him.
kim go eun was a SURPRISE! i have only watched her in Goblin and then now in The King : Eternal Monarch. both shows that i don't really like, in fact i dropped the latter. so to see her here was refreshing. she was very natural and believable in her performance.

Also, special mention to the direction and editing of this movie. the way it was done, this felt so much more personal instead of watching a movie. it felt like i'm taking a small dive into the personal lives of these two characters and i'm there with them, seeing them experience these emotions and conflicts. so kudos to that!

Issues (spoilers) :
Now to the negatives. I'll just point them out in a list, cuz i'm tired of typing and this already feels TOOOOOOO long!
— the last break up felt so unnecessary. there was no reason why the FL would leave him out of the blue when literally a scene ago she wanted him to stay with her and not visit that family anymore. it felt like this was done just to create drama for the final climax.
— the villainization in the last twenty minutes felt really out of the blue. served literally zero purpose to the story and also ruined the beautiful friendship the FL had with him.
— i wished they had explained more about what the friend meant when he said "only the ML was forgiven" for the mistake.

so, all in all, i am giving it a nine, even after all these issues, because this really was my cup of tea. i loved it bc i'm a very character-driven stories lover. it had the characters, it had the chemistry. i was sold!