Thanks, @Crell, I'm glad you asked!
Nontrivial Excel usage is quite obviously programming. Come on. But beyond that:
We’d have a much better understanding of usability failures if we understood tiny UI actions as itty bitty moments of programming. We’re asking people to momentarily span the bridge between human understanding and machine execution. Pretending that bridge doesn't exist is a perennial footgun.
“What, even clicking a button, Paul?!?” Well…