bmt

I started this movie and halfway through jumped to the ending.... and because of that I got confused. I thought there was a parallel world. So, I rewatched it in full without skipping.
The movie depicts the difficulty of having a relationship that neither of them had been open about with others. The slimmer Hyeok never told anyone he has a girlfriend back home which led him to entertain the temptation and the suspicion.
We may say that the Jang Hyeok and Dae-un both had lost their way because of their failure to communicate honestly. The moment the man started to lie, he is sure to hide something and later on yield to temptation.
Perhaps we may wonder now, what will happen to the chubby Hyeok and Dae-un, about the baby Dae-un carries and the slimmer Hyeok.
The last part of the movie which is a sort of a recap of all the events from the beginning of Dae-un's encounter with the first Hyeok up to going to the airport with the second Hyeok clarified everything.
Figuring what is the sweet part? Perhaps the start of the relationships that brings butterflies to each other.
It seems that more of the movie tends to the sour part - a relationship gone wrong, cheating, too late to realize she is the one and losing her to another who now benefited the Christmas time in Jeju.
I wonder why the writer thought of this title anyway.
No need to rewatch, as it didn't give me a positive life lessons. sorry.