I have never sworn in therapy before, and my T followed my lead in the beginning when she was getting to know me. But occasionally she does swear and it actually always shocks and even scares me a little. I think it's because it conveys strong emotion, and the thought of my T being angry scares me. I think she has done it before to maybe show that I could swear if I wanted to, and she probably thinks I'm too repressed and polite for my own good or something. In real life, I swear on rare occasions.