I have taught a course in the summer almost every year I’ve been a professor, and I’ve always enjoyed it. Well, almost always. And it’s not just because of the extra money.
For one thing, the classes tend to be at just the right size, around a dozen or so. Smaller than that and there are not enough ideas to sustain the discussion; too many more and people feel intimidated and reticent.
The students, too, are often better in the summer. It’s a matter of motivation: if they are driven enough to pick up extra credits in the summer, they’re likely to have the wherewithal to do the readings and, you know, actually think about them. Such students often do very well in these courses, too, because when it comes to exam time, the material is fresh in their minds. We just covered half this stuff last week!
It’s not all joy and fun, of course. I have not, for example, been able to keep up with mowing my lawn lately, and it’s sometimes frustrating when students are taking your course because they need three credits of something, anything, to graduate. But on the whole, I would hate to miss that brainy season in the sun.