Why so attractive

Watching it for like the twentieth time, I questioned why I like this movie and this actor so much. I looove Cha Taehyun, I adore Jeon Jihyun, and I really like the movie. Why are they so attractive? 

It is puzzling especially because they don't fit in with the stereotypical expectations of masculinity and femininity. Gyeonwoo is obviously nowhere near what would be considered masculine throughout the movie. His attempts to gain masculinity is continuously thwarted by his family and friends (and his 'girl'). He was raised like a girl because his parents wanted a girl; he is treated like a kid by his mother who always hits him and yells at him, always making him cower and run away; his girlfriend always beats him up, and he rarely (if ever) wins against her. Even the 'movie' ignores the narrator and progresses onto 'Second Half' of the story, although Gyeonwoo wants to continue his explanation. The 'sassy girl' is sassy to put it most gently. The Korean description used in the title is '엽기(yeopgi)', which can be very roughly translated as bizarre and grotesque. She is loud, violent, outspoken, authoritative, threatening, etc, but as I grew up, I had always seen her as a 'role-model'. I simply found her so attractive. (Exactly because she was so not feminine. But this is for another discussion.)

I am a little sceptical of how the movie ended, however, with sudden gain of femininity and masculinity of the two characters. Why did the 'role-switching' between the two characters have to come to an end for the resolution of the movie? The girl we see at the end of the movie is not the same 'sassy' girl she used to be. "After all, [she] can't help it... [She] is just a girl after all..." The Gyeonwoo we see at the end of the movie is not the same clumsy, inept man to be pushed around by his mother and aunt. He, in the end, is the one who is recognized as a writer. He becomes more skilled with squash, kendo and swimming, and he chooses to in the end go see his aunt for a blind-date. In fact, it turns out it's Gyeonwoo from the future that puts the bridge between Gyeonwoo and the girl by telling the girl about the secret of the tree. (Look up "The Weaver Girl and the Cowherd" if you are not familiar with the story of  "Gyeonwoo & Jiknyeo". It's the Chinese/original version for "Gyeonwoo&Jiknyu")

Honestly, though, I never found this to be troubling until now. Perhaps one of the reasons why the role-switching between the two can be accepted and laughed over is because it is overridden by the return to the stereotypical expectations at the end. 

But then... I had hard time taking serious notes on this movie as I was too busy being emotionally affected by this movie (fan-girling, ehem).