In my case, it was a very difficult exam written by a young professor who didn't understand our limitations (and who went to a school without grades where -- he admitted -- he always thought "impossible" exams were the most thought-provoking). I hadn't slept a wink the night before and came in very anxious. By the middle of the exam (after the twelve short answer and the first essay, a philosophical essay), I was staring at the clock watching fifteen minutes pass by, hot tears running down my face, frozen in my seat. It was really disappointing as this was by far my favorite first-semester class.