I have made this mistake, not intentionally, but I have done it. My plate is full with creating new cirricullm, I have students having a hard time grasping the material, I have another instructor call out, and my anxiety shines on through. When this happen's, immediatly it shines through in my students. So it is SO important, we as instructor's, stay focused on what we are doing at that moment with the students and let nothing eles filter through. If we don't our students start carrying the same anxiety