In one of my Mid Term exams, I started writing the last question, came to the end of the first Answer Booklet and then realized I would need to borrow a four-page-foolscap-paper supplement sheet just for writing 2-3 lines and a small diagram. However, the diagram was quite necessary. I usually try to plan my last answer such that this kind of a thing does not happen. This time I forgot that I was writing the last question.
I was then seized by a very very strong urge to scribble in the margin: "I have a truly complete solution to this but the margin is too small to hold it" and walk out of the room! Man, the sheer pseud value!
But of course I didn't do it. Now it is one more thing in my "To-Do" list. (sigh!)