I know I don't get along with my sister at all because of a deep seated childhood resentment of her even being born, taking away parental attention from me and later being really annoying. As such I have treated her cruelly my entire life. Some guilt about how I treat my younger sister is brought forward when you make me reflect in threads such as these, but I doubt we'd get along anyway, we are alike and yet not compatible to be good siblings.
We don't fight so much physically anymore but I do give her some verbal abuse. Don't think she's all innocent victim though, the girl dishes it out as well as she takes it, which is remarkably well, she can be a total female dog when she wants to be. Perhaps having a borderline abusive brother stimulated her to succeed, because she's nicer, smarter and more emotionally stable than me. Or, more likely, I am a jealous bully who has always known that and has tried to put her down.
Sometimes we get along ok but god damn Japan and its creepy Onii-chaan big brother-little sister thing has creeped me out too much, I will always be mildly disliking and at loggerheads with mine, it's how siblings are supposed to be. I have more extreme and cruel animosity than most but hopefully when I move out I will never have to see my sister again and we can live separate lives.
