What's My Thing, I Wonder?

Kate (that is, Ms. William), her thing is that she doesn't blend her eyeliner. My one friend wears lots of faux diamonds and thinks that people think they are real but really everybody knows they are fake. I have another friend that tells the same stories - long stories - over and over and over again. I must have a thing that is relatively annoying that people notice but don't tell me. I wonder what it is.