Although none of my training is in the Theatrical Arts, I must admit that acting is a large part of my teaching style. I have even let the students in on that little "secret" - with some of my students it's not the best idea for them to act like they do at home. I encourage developing a professional persona that they can be, instead - at least until their employers have had some time to appreciate the good work that they do.
I let them know that although who they see instructing them, yes, really is me; it is not who I really am all of the time. Work stays at work and home stays at home.
On other dramatic issues, yes, one definitely needs to "ham it up" just a bit. Fun helps material get locked into memory (from my experience). Funny helps bring some of the borderline students back to class. The classes that students do not enjoy because they think the instructor is "mean" or too distant are often simply skipped, and then grades begin to suffer quite badly (then the "fun" teacher has to diplomatically field questions from students about "why that teacher is so [insert adjective here]" - that is a tight rope walking experience.)
