Even as I wrote the word on the student paper, I knew it was a bad idea, but I couldn't stop myself. I've been grading essays for three days straight (my fault--I assigned 'em!) and I've had many opportunities to write "vague" or "unclear" or "redundant" (such as when the student wrote that a particularly literary work "portrayed the way nature is depicted," which is either part of a complex argument focusing on metaliterary concepts or simply a sloppy sentence), but rarely do I have the opportunity to apply to a student paper the phrase "charmingly insouciant." And it was a freshman paper!
The problem with writing "charmingly insouciant" on a student paper is that the student might not know what "insouciant" means--might even consider it vaguely insulting. That's why I appended "charmingly": as a hint that insouciance is not a flaw, at least in this case. I can imagine contexts in which insouciance, charming or not, would be inappropriate, but a freshman essay in a class devoted to the topic of humor can be as insouciant as it wants to be as long as it fulfills the requirements of the assignment.
Funny thing: over the years, literally hundreds of desperate people have blundered onto my blog after typing into a search engine the phrase "how to use suave in a sentence" (and now I'll attract even more!), but no one ever asks how to use "insouciant" in a sentence. Why not? Suave is shampoo. You use it on your hair. Insouciance serves in many situations, including student essays on the purpose of humor.
I've been reading too many essays that don't even come close to insouciance--that live in the land of the bland, the nation of the vague generalization, the locus of lack of focus--so when I encounter a paper appropriately employing charming insouciance, I have to applaud. I trust that a student capable of writing with insouciance is also familiar with the term, but if not, she'll learn something new. That is, after all, why we're here.