Edward Dolan wrote:

...
When I was in college I was taught by world famous professors and I was also
taught by graduate assistants. The graduate assistants were all worthless as
teachers and some few of the world famous professors weren't half bad. That
is the difference, you nut case!...

And some world famous professors are excellent researchers but awful
teachers, and some teaching assistants do a very good job.

--
Tom Sherman - Curmudgeon and Pedant