. . .did your parents, or perhaps their lack of involvement, have anything to do with it?
I see some comments on MN saying you can't guarantee siblings will get along, but from people I know, and my own situation, the bad sibling relationships were down to the parents.
For example, my older sister had been bullied throughout school and, as a result, she then bullied me (this is my reflective reasoning for it as an adult). There's 6years between us and from her age of around 14/15, it's like a flick switched and she became very nasty and even physically violent towards me. My mom would witness it and not say a word until things escalated terribly. Even then, she'd just step in and shout something like "I'm sick of you two fighting!" even though the reality was an overweight 16year old was pummeling a stick thin 10 year old who was curled up in a ball trying to hold on to her hair being dragged out and protect every other part of her body.
As a result, I'm not close with my sister at all. Would never spend one on one time with her.
I just can't fathom why my mum wouldn't have nipped things in the bud when we were just at name calling stage, or even sooner. I think we'd have had a much better relationship if so many unkind words didn't have a chance to be said and physical abuse didn't have a chance to happen.
In other scenarios, one sibling is clearly favoured, there's unfair treatment, nothing done to foster a reasonably close bond, etc.
Are there people who have at least a bit of a dislike for their sibling/s despite their parents trying to prevent it? I'm not referring to siblings who are just quite different, moreso relationship issues.