Chapter 1: I liked Sunny a lot, though it's not a movie I'd watch several times it was still a pleasure!
I think the reason why Nami was so obssessed with trying to be friends with Suji too was because of the fear of not being in the group at all if Suji disliked her as if she had the power to kick her out, though I believe there was gay subtext with that girl, Sung Min toward Chunhwa, she was literally ready to hurt Nami because she "stole" Chunhwa from her when in fact she was too blinded that she didn't notied that she was the one who withdrew her friend from herself.
I can't really see how they could have formed the friendship in another way to stand out, I mean it seemed like a normal group of friends, though it was a shame that they only showed the bond from Nami perspective, I mean when I saw the movie I was much more moved over Chunhwa and Nami because they didn't focused much on the other girls and we didn't even get to see how the girls bounded before Nami's arrival especially when Suji was so reserved and barely talked to the other even if she hung out with them.
I was a bit surprised over the reason why the girls split because of Suji's injury/scar, but it showed that even a group of friends with a "strong" bond could lose touch over the years for 'small' things.