Whenever I substitute another teachers class I begin with anxiety wondering if I'm going to teach a class that will like me. Will they like my vinyassa style? Will they enjoy the pace? Should this be a light class or a power class?
To help me calm, I meditate at the front of the class. I feel the class, I let the auras of the students sink in. I listen to their conversations, I listen for laughter and lightness. I also listen for silence.
Then I simply be me, let the mood take over and modify the class to fit the students. I have never been disappointed. We are all amazing, but without fear and without trying new things, we will never know our capabilities, our greatness, our joys and our weaknesses.
Substituting class enables me to do what I sometimes ask my students to do.
Step out of your comfort zone, try something new, you never know unless you try. :)