Cats groom themselves, right? There's sharing tongues, right? So why aren't there any hairballs?

* OK, I've thought about this one over the years more than I'd like to admit. No, I don't want detailed descriptions of hairballs. Yes, I want at least comedic mentions of them, like oh, X character got another hairball yesterday, maybe they should stop licking themselves for once and actually contribute. Literally just any reasons to justify the fact they are cats and not humans.