As a young teenager, my younger sister, “Claudia,” had the typical “I know everything and you know nothing” attitude. She was always right and everyone else was dumb. She would argue with everything you said, no matter how neutral. As she got older, she became more mature, and would only get snippy like before when she was in a bad mood (although it happened fairly often). When she matured, she and I became pretty close. We have a lot of similar interests and similar tastes, so it was fun to spend time with her. However, even then she would revert to her old self when she was in a mood. I learned just to end the conversation when she got like this, because there was no way to make her snap out of it. After a while (anywhere from an hour to a few days) of steering clear of her, she would return to her usual fun self.
Today Claudia is 20 years old and in college, and she is still often difficult. She’s at home for the summer with our parents, and she seems to be in a mood most of the time. She’s even been difficult with me, and I am usually the one who gets along best with her. Both of my parents have separately brought up to me their frustration and annoyance with her behavior. We all figured she would grow out of this behavior, but it doesn’t seem to be going anywhere.
I’m worried about Claudia. I don’t know if she has any friends at school (she never mentions anyone and we talk about everything). Still, it’s hard to talk to her when she’s so unpleasant to be around. Lately she has been staying in a bad mood longer and we haven’t been talking as much.
Is there a polite way to tell her that her behavior isn’t okay?