Explanations/etymology also appreciated!
For Joe Shmoe, it means a very average or below average person. It’s a derivation of the practice of using “shm-” to dismiss something (eg “Practice shmactice. We’re already perfect”).
And “John Smith” is meant to be the most average name or person imaginable, so they have the “most common” (citation needed) first and last name as well.
I’d attest to that Juan de la Cruz for the most generic Filipino name. de la Cruz still works as a very common surname though I don’t think Juan is still used as much as back then.
And then there are the placeholder phrases, all of which I’ve heard and used.
Uy, ku’nin mo ang ano, yung kuan, iyon! Ay, ano nga ba ang tawag d’yan? Noong ninety kopong-kopong pa namin binili iyan kina ano… Ano nga ba’ng pangalan niya?