Cripe, who was teaching those classes? Did they even understand the amount on their own pay stub at the end of the week?
Either that, or it's failures who just is in class to collect a paycheck and don't care if a student wasn't learning.
Don't think I had any like that, esp not those in high school, but I'd at least seen substitutes who did not give a crap, including one who gave up and didn't bother trying to each much of of anything... We didn't mind at the time, but at least he was just a temp.