I've gotten a couple of warm fuzzy emails from students. One said:

Thank you for your hard work teaching us the last couple of months. I really feel as though I have learned a lot about technical and professional writing.

Another said:

I learned a lot in this class in terms of technical writing. I don't like writing but now I tend to like it. I hope this will continue.

They may be ploys to get better grades, but I hope not. I did work very hard teaching this summer, and now I feel as though it was worth it.