Everyone’s had the experience of some professor who seems so talented in his field that he sees teaching as frustration. No amount of research or deep, esoteric knowledge can quell their annoyance at teaching how to properly use a comma.
Choke was the first book I’ve read on this issue. It really effectively broke down just how this process manifests. Basically, when people become skilled at an activity they’re unconsciously competent. English professors don’t contemplate their essay structures, and instead they come as second nature. In effect, they’re unable to empathize with those who are consciously competent. Due to some teacher’s not being cognizant of this disconnect in skill, they inadvertently skip over critical steps, and take their own skill for granted. Ultimately, this was the book that made me realize (perhaps late) that teaching is an art form in and of itself.