At GMU, I was teaching traditional subjects (econometrics, macro) to non-traditional students (austrians and public choicers). Many of them thought the whole enterprise was invalid and were not shy about saying so or giving heated critiques of what exactly was the problem. It was great for me, because it forced me to figure out why I thought my subjects were worth learning. Plus working to convince them that even if they disagreed, there were worthwhile things to be learned and even appreciated in the standard material definitely made me a better teacher (thanks Pete and Steve and Dave!!).
At Tulane and at Oklahoma, a lot of students had the opposite problem: they thought all published work was perfect and all famous professors infallible. Here I had to work to convince them that (a la Tyler) there is indeed something wrong with everything, existing work can be improved upon, even by non superstar economists, and that a critical eye was extremely important.
This past fall though, I realized I may have gone overboard with pushing critical thinking on my students. Mrs. Angus and I started a reading group in development and growth where we meet to discuss recently published or new working papers in the fields. And some of the students didn't like anything! I am a critical person by nature, but the level of negativity in the group often disturbed me. I once again found myself trying to show students that there was value to be appreciated in other people's research, no matter what one thought of its overall validity.
Full circle, people!