It’s a joke. They are pretending they can’t remember the very obvious/absurd/silly/etc thing, so they have to check their notes before finishing the thought.

I think it might have its origin in courtroom dramas having prosecutors being catty with the defense but that’s just a barely informed guess tbh

Aerial Troubles (In My Ass) - Stereolab

As a great and nameless character on Cowboy Bebop once said; “seems that way”.

As an ungrateful little urchin, I would have been pissed ngl. As an adult tho, I can see that this is so freaking sweet and cool.