I'm going to call my sister a polar bear
You could be hurting your sibling a lot every time you call them a name.
I really wish I was not related to it. I don't respect her existence.
Have you thought about how it makes your sister feel when you call her these names? You could be hurting her greatly every time you do this.
It's fine, I don't like her anymore anyway.
But she is your sister, don't you want to make good memories and make your parents happy? What you are saying can be very hurtful to your sister. I'm just saying that she might love you very much and she wants to have a good relationship with you.