Dang, what with the hate on Hiiragi ? What she does is pretty understandable. Imagine having your twin who always relied on you suddendly becoming better than you at everything but still thinking she is worthless without you. Hiiragi is just angry that her sister can't realize how good she is and instead insist on puttting herself down. Imagine how frustrating that is, having someone who is better than you but insisting on telling she is bad, it's extremlyfrustrating.
Sure, but . . . there they are, so close to each other as to exclude everyone else, she knows she's by a mile the most important thing in her sister's world, and she never bothers to say a single word to give her twin the slightest clue of what was up in her head before dumping her cold. I don't see how you can bitch about someone being frustrating if you've never given them the slightest hint that they're frustrating you. "Acting vaguely sullen" is not a hint because it gives no clue why you're acting that way--might have meant she had a philosophical crisis of meaning, might have meant she was being abused by a teacher, could be anything.
And I mean, it's clear Tsubaki would have altered her behaviour in any way Hiiragi asked, and that it was totally obvious she would. So if she didn't like how their dynamic was playing out, she could have said she wanted a different one and that would have happened. If she didn't know what she wanted, she could have at least talked it out. Instead she runs this deception with no purpose except to delay Tsubaki finding out until it was too late for her to, I dunno, re-switch or something, not apparently caring that the collateral damage is Tsubaki not getting into the school she wanted . . . although, come to think of it, even that school wasn't Tsubaki's own choice, it was Hiiragi's pick, so she was yanking her chain from the beginning.
Basically, this is Lucy / Charlie Brown / Football stuff except she's yanking away their relationship instead of the football.
