Summer session has ended--all except the grading, of course. As their final papers came in, I read and reread their messages, especially those who said they'd enjoyed the class or learned a lot or wished me a good summer (or all three). The papers may be another story, especially those who seem to have completely ignored the advice I gave on their drafts, but the messages were a pleasure.
Nobody I have ever met teaches summer school for the Joy of Teaching; you volunteer for it so you can make enough money for plane fare or what have you. And yet at the end of the day, it gives you pleasure to see that they liked or learned from (or both) materials that you worked hard to put together or that your feedback on their work was helpful.
Yes, they could be apple-polishing or hoping that a nice message will help them in the end, but I'd like to think this isn't the case.
And, best of all, we'll all shortly be done.