Sisters Who Feel the Need to Prove They’re Better then You

I have a twin sister, and today I asked her if I could borrow a pair of shorts that don’t fit her anymore. She said I could if she could wear a nice belt I just bought for myself that I had previously made clear I didn’t want to share. I asked why she wanted to wear that one when she had a belt that looked almost identical. She responded with “I don’t care about the belt I just need to show you that I can take whatever I want from you.”