I had this happen in a college class once (B in an easy/basic course). It came down to one exam where the teacher took off a large number of points on a big problem. I made a stupid mistake so the answer was wrong but he should have taken only a couple of points. His interpretation was that the work I showed indicated that I didn't understand the problem or how to solve it. He was wrong. I tried to talk to him about it and it was like talking to a wall. I was pretty furious about that because I felt it was unfair. I also knew that a lot of the students in the class traded assignments with each other, had prior exams, etc. In other words, they were cheating. Haha - I'm getting mad just thinking about it again. In the big picture, it was of two Bs and didn't really matter though.
EDIT: I'm pretty sure he wasn't an ENFP though . Just a crappy teacher.