When I started teaching, I was 22 and I literally had to practice my “tough” faces in the mirror before school. I’m now in my pre-40s and I don’t have to practice anymore.
In fact, over the last snowstorm, we passed some time playing with costumes, and when I put on my old Snow White costume, spoke in a very soft voice, and watched my own kids quickly fall into line as they tried to impress the princess. In fact, there is much discussion of expanding my wardrobe to include the princess who reads (Belle), the princess who is tough (Mulan) and the princess who swims (Ariel) although I’d have to work on that voice.

