When I was teaching, the scary thing about being sick and missing classes was the possibility of getting the wrong substitute. It was a real possibility, mainly because they only paid eight bucks a day, and the only requirement was a pulse.

Fortunately, we had some excellent people who were willing to work for that -- I never understood why -- and I only got the wrong sub two or three times in 33 years.

The wrong substitute is the one that leaves all of your plans stacked neatly on the desk and takes off in another direction. I had one that brought a VCR to school and played movies all day.

Another one had some students reorganize all of the science equipment. I think that's the same one who turned my grade book over to some students and told them to average the grades.

But principals don't call substitutes that teachers complain about, so you don't get those people twice. My favorite substitutes were retired teachers. You come back from the flu and find your class room in order, papers graded, and actual teaching has been done. Some college students who are planning to teach also do a good job, but it helps if they look older than the students.
Howard