I understand what you're saying, grydth, but I'm uncomfortable with this general approach to teaching. I've taught university on a full-time basis for close to twenty-five years, and in the course of that time we've had graduate students whom we felt we just couldn't admit to candidacy in our doctoral program, because their performance to that point didn't warrant confidence that they could complete a Ph.D. dissertation that would be up to standard. In such cases, we have to provide meticulous justification to the student explaininng our decision. Conversely, when a student, grad or undergrad performs well, it would be unconscionable on our part to give them a low grade simply to motivate them to retake a class to do even better. There is no way that we could justify a failing grade for a `pretty fine' performance. You don't give a student who's earned a B+ a failing grade just because you're pretty sure they're capable of an A, much as you'd like to take them by the shoulders and shake them in frustration. And as I say, if the grading standard were either A or F, nothing else, we would take it for granted that we would explain to the student in explicit detail just where they fell short if they hadn't done A-level work. We are trying to teach our students a difficult and complex subject matter; turning it into `read my mind!' would be totally unacceptable to us and destructive to our task.
My feeling is, if there's a particular place you fell short, your instructor should explain exactly what that is. In the case of Addison's daughter, it seems fairly straightforward: the staff techs weren't up to par. OK, that's fair, and the instructor did make it clear what the problem was. But if a student's good performance treated were as a subpar performance with no explanation given, or an instance of `let's see just how much disappointment you can swallow silently', then I would have a problem with that, and it would convey a statement to my child that I would not want him to accept and internalize—e.g., I wouldn't want him to grow up to be the sort of person who would do that same thing to a subordinate in a job evaluation in the office they both worked in, for example...