When I began teaching economics something struck me during the first week. I knew a fair amount about economics -- much less than I thought -- but I had received not even a minute's worth of instruction on teaching. All I could think to do was read the book, more or less explain it in my own words using examples not in the book, and answer questions. There were no war stories for a first year teacher of microeconomic theory. One thing that gradually occurred to me is that a knowledge of economics, and then later of law, only accounted for about 66% of what I did as a teacher. And it also occurred me that while students see the professor while he or she is teaching, they only witness about 66% of what goes into teaching.
Other courses, common sense, and day to day experiences inform teaching yet their importance remains behind the scenes. One of the most useful courses I took was a required freshman level course in logic. I am not sure it is required or even offered any more but it did mean that I do not confuse causation and correlation. It also meant that I do my best to correct students who reason like this: "The professor does not need to take role because I attend regularly" Bizarre, right? But I have heard the very same "reasoning" from law professors. For example, "There is no need to have a rule requiring professors to take role because I already take role." I assume professors finding this acceptable also find it acceptable in class.
This also relates to the point that students see only about 66% of what goes into teaching. Suppose you give a machine graded exam and there are 10 reasons that could explain a wrong answer. If most of the students are getting it wrong for the same reason, it suggests an opportunity to improve one's teaching the next term. (Unless, of course, the goal is not really to teach but to get a good distribution.) I assume the machine graded test givers just plow along without pin pointing the problem which may reflect their teaching as much as student diligence.
The all time prize for irrational testing actually goes to essay test givers who say something like "Answer 3 of the next 5 questions." There are many combinations of 3 out of 5 and each one represents a different test. In addition, a student could get an 80 of 100 on all five and do worse than a student who scores and 85 on three but would have scored a 60 on the other two. Pretty simple, right? This is, however, popular with the students and you know where that can lead.