I think they are trained to handle the brunt of our emotions.
I know I'm realllllly sarcastic, and have to restrain myself from making the comments I would otherwise make when I'm in session.
Off and on, they do slip out... and I catch my T offguard with them. I left T speechless a couple times. In retrospect, I feel really bad- but at the same time, I'm kind of glad that she's probably going to understand my disposition a little better.