When I was a reference librarian, I did not have a class to teach, just cameo guest shots in other people's courses. I thought it was touching and kind of cute when a cetrtain professor I knew would come by lamenting the quality of his exams. He took it very personally, as though it were a personal affront that his students had failed to learn. Now that I have courses of my own to teach, I have a lot more empathy for this guy. It's hard not to take it personally when a student blows your course off -- obviously never having paid any attention to the things said in class. It even hurts when students (or colleagues!) dismiss books or webographies purchased or created by the library. It's like saying your work or whole life, even, are worthless. I am trying to take a long view, and not take it personally, but boy, it's hard!