Once again, what started as a comment over at Chizumatic takes on a life of its own.
As Muon and Jordi note, YnS is following the omnibus format. In each of them up to this point (except the maid’s arc, told in omakes), Sora reaches a point where she realizes she has to let go of Haruka, her twin brother. In her arc, which branches off the “childhood friend” arc, she doesn’t let go, and we’ve now reached the trainwreck; two of their classmates just walked in on them, in flagrante delecto.
I’ve noticed something that I suspect was deliberate — spoilers: Show ▼
And finally, another spoiler, but below the fold:
The bizarre and especially tragic thing is that it’s only in the final arc that Sora becomes much more than a bitter, withdrawn girl. In each of the other arcs, she lets go unwillingly and unhappily; she becomes more autistic-like and anti-social.
Her own arc is the only one we see her laugh and smile in. Not only that, she stops being lazy and self-centered, in order to take care of Haruka. She cooks, she cleans, she tries to make Haruka happy — and I’m not just talking about the sex. Essentially, only by giving in to her most selfish desires (and thusly, getting what she wants the most) does she gain the strength to grow up and be anything more than a spoiled, clingy child.
I’m not sure how the trainwreck is going to work out for them, but the most pitiable character in all the combined story arcs is Sora, and it may be that pity that’s influencing my opinion of the series thus far. I’m witholding my grade until I’ve seen the last episode, but it might be a bit higher than even I expected, going in.