Starting From Zero, Again

This comment, from a postdoc, on Monday's post intrigued me:
I think it would be depressing to teach a similar course over and over again. It would feel like every year you go back to point 0 and have to start with another set of ignorant students all over again.
In fact, it's not depressing at all. Sure, certain aspects of teaching the same course over and over can get tedious, and that's one reason why many of us make changes to our course content from time to time, but, at least for me, it is not depressing, and certainly not for the reason the postdoc proposes.

In fact, that's part of the fun of it for me: hitting reset, starting over, beginning with a new group of students who don't yet know the awesome things you are going to teach them (this is not the same as being "ignorant"), and then watching them progress through the term. If all (or most) goes well*, it can be very satisfying. Surely there is an annoying analogy involving gardening/farming and the seasons, or something like that?

[* that is, not too many high-maintenance students, no cheaters etc.]

It's the same with advising grad students, and that's not depressing either.

Does anyone agree with the postdoc about feeling depressed (or other negative feeling) about having to start over at "point 0" with each new group of students? Or perhaps people who feel that way won't pursue a career involving teaching(?). And if they do pursue a career involving teaching, will they always feel that way, or see that, in fact, the rebooting aspect of teaching is not depressing? It would be particularly interesting to hear from someone who thought that it might be depressing to start from the beginning again and again, but found that it wasn't. Or vice versa.