I don’t ever “become” the Mugger, but the Mugger overlays my teaching self as a mask. Behind the mask, I’m observing the student and gauging her reaction to the Mugger. Whatever I’m saying to her is superficially genuine in the same way a good stage actor is being true to his or her character. And just like an actor on stage, I’m not the role, I’m playing the role. While I’m playing it I’m paying attention to all sorts of other things specific to the class. Of course, over the years, I’ve developed, as have other suited instructors, a repertoire of stock characters that I can go to for different purposes. The key is that we use them deliberately, and the point of the interaction is always what will help this student in this fight to learn something and get better. It’s never about the character itself.