Students tend to like everything neatly laid out [...] they want the answers.
But sometimes (although not always) effective teaching involves the
deliberate inducing of confusion, the withholding of clarity, the refusal
to provide answers; sometimes a class or an entire semester is spent being
taken down various garden paths leading to dead ends that require inquiry
to begin all over again, with the same discombobulating result; sometimes
your expectations have been systematically disappointed. And sometimes
that disappointment, while extremely annoying at the moment, is the sign
that you’ve just been the beneficiary of a great course, although you may
not realize it for decades.
--- Stanley Fish
    http://opinionator.blogs.nytimes.com/2010/06/21/deep-in-the-heart-of-texas/