Now I’m not a professional teacher or lecturer but I bet the hardest aspect about teaching adults is the incompetency part.
The students aren’t able to replicate what the teacher displayed or they’re not quite grasping it as quickly as their classmates and so they beat themselves up or sit out or disrupt the class or yell in frustration.
Some students will accept that in order to reach a higher level of competency one must first be incompetent but not all.
For some, the flirtation with incompetence is like being flayed alive.
Thomas Duggan 