It definitely does depend on the prof, but I've also had the opposite experience.
A lot of lower level profs are forced into teaching the classes due to lack of seniority and other reasons. Intro courses, to a PhD, are the worst things to teach.
Junior/Senior level courses, on the other hand, are slightly more in-line with the prof's knowledge and skills and also are taken by people who will probably graduate in a similar subject.
That said, undergrad courses are still menial labor to profs. Many profs are really there to reasearch and don't want to teach but are forced to....they tend to be asses. Many enjoy teaching, they are cool.....
b
|