Maybe it’s a genuine CIDU? But I think that punch line is all there is.
I think we all can sympathize with Duane’s motivations for his … little prank. And that’s the main joke, which is not in need of explication; so this isn’t quite a CIDU. But if we wanted to get into it a little, we could ask whether he’s getting revenge more on the kid or on the mom. And at the practical level, what does it mean that he still has the barber’s customer-apron as he’s leaving?
I guess this Working Daze fits an offshoot of the “CIDU-Quickie” category, where the joke is utterly incomprehensible until you are shown (or realize you already know) an instance of something-that’s-going-around, and then that entirely exhausts the mystery.
Linked here is a compilation of what lies behind the joke. (I can’t watch this all the way thru.)