In elementary school, you dream that the teacher doesn't know your name.  In middle school, you enter a nightmare world where you show up to school with raging acne and everyone knows but you.  In high school, the nightmare matures as much as you have and involves having a final exam in a class you never attended. As an instructor, it becomes far more sinister... showing up for a class without lecture notes, or having not prepped for the day at all, or being forced to teach organic chemistry when you normally teach Latin American poetry.