I think I remember that Hiiragi hates Tsubaki 'cause she thinks Tsubaki's better than her. Since Tsubaki looks down on herself, Hiiragi is pissed since that makes her even worse or whatever. Wait, and then Tsubaki hates herself since Hiiragi hates her? But Hiiragi starts hating her because Tsubaki hates herself?
So, you're basically right referring to the reason why Hiiragi dislikes Tsubaki. Just like any siblings, there's the moment where one of them excels a lot better at everything they do which is Tsubaki in this situation while Hiiragi is being left in her shadow. Like you said Hiiragi doesn't like the fact that even though Tsubaki is good at everything she fails to appreciate herself. Therefore since they're twins it's like Tsubaki doesn't respect or like Hiiragi because they share the "same face". It's confusing to put in words because of the concept but if you reread the chapters that explain it you'll understand better.
I see. That makes more sense, and it's understandable why Hiiragi's mad and all. She's definitely way too pissed at her sister, but, still, that does make sense. I'm still a bit confused by why Tsubaki hates herself. I thought she started hating herself since Hiiragi hates her, but I probably just forgot what the real reason was (if they even explained why yet) since that doesn't make too much sense in this context. I'll definitely have to reread the chapters that explained all this.
While this is a comedy, the angst with the two main girls shows that it takes its angst seriously, so I’d bet that whatever their breaking point was it wasn’t something like that. Although I am assuming that you mean it in the anime jokey-pervert way- so if the manga made it the realistic super creepy way it could actually be that.
Yeah, I see what you mean there. I meant it in the jokey way, but it would definitely make more sense if it was actually realistic. I still doubt that's the real reason, but maybe it is...