Courtesy the Volokh Conspiracy, I read a great recollection of student evaluations by law professor Eric Muller at U. North Carolina.

The question for the students was "Is the professor able to impart the subject matter (e.g., communication skills, organiation, responsiveness to student questions, stimulation of interest in the subject matter)"

This student's response: "Yes, but he is kind of like the hippie teacher from Beavis & Butthead in his delivery."

This reminds me of my favorite answer on my student evaluations. Asked to evaluate the examinations and assignments in the class, a student responded, "He pulls his essay questions out of his ass." This bothered me some -- it takes me a long time to write a good essay question -- and I mentioned it to my wife. A few months later I woke up one morning and, as is my wont, grabbed the Wall Street Journal and headed to the bathroom. I read an article that made me think of an exam question for my macro theory class. I said this to my wife at breakfast and she said, "That student was right: You do pull exam questions out of your ass."