My sister is nearly 50. She's always been temperamental and angry, hostile, and bossy, getting defensive over any statement, prone to expletive-ridden tantrums. She likes to call my mother a ****** and even the C word. Unfortunately, even at her age, it's like dealing with a toddler, however, a very loud, paranoid one.

There's no way to tell her how I feel because she'll immediately throw it back on me. For example, if I say "I feel like a scared defenseless child when you ****** me out," she'll say "Well, you make me feel like an idiot." There's never an attempt to understand my viewpoint. And I have given a LOT Of thought to understanding her situation. I have given her chance after chance to be somewhat civil. It never happens. She's mean, she's funny and sweet, she's mean, she's funny and sweet. It's a never ending cycle.

My mother thinks I should be able to let this behavior roll off my back. I told her we teach others how to treat us, and I will not teach her that it's OK to treat me like she does. My mom nearly cried when I said I don't want to spend Christmas with my sister and her.

What do you think? Should I submit myself to abuse just because she's my sister?