I think it’s the demoralization after the semester when you feel like you put in a herculean effort (on an adjunct salary) trying to drag a large class of recalcitrant students up a hill and not only did 40% of them basically fall down the hill, but they whined and complained in their evaluations and blamed it on you, after not really doing what you told them to do in the first place.
In reality, any of a variety of methods will work if the students hold up their end of the effort. They should be motivated by the fact that this is what they need to do in order to get where they want to be. Or by the undesirability of the alternatives, for the large contingent of disadvantaged minority students.
In some of my RMP reviews, students have used the phrase “she doesn’t know how to teach the material”, which is true in the sense that I don’t know how to teach it in the way that they seem to want it taught. I don’t think ANYONE knows how to do that, but they are too young/inexperienced to realize that what they want is not possible.