Nothing angers me more than cute exam questions designed solely for the purpose of telling other professors about your clever question next time the topic comes up. You put students through months of reading and hard work, have them work hard to memorize all kinds of doctrines for exams, and then come up with some bull 2 line question or quotation and tell them to right an hour essay on it.
There's no way to justify this kind of exam. The only skill it tests is an ability to bull effectively for an hour. This is a pretty useful skill at most jobs and in life in general, I know, but nothing makes me angrier than studying for hours, taking endless practice tests, knowing all the material, and suffering because a professor wants to prove how clever he or she is.