Sometimes when I'm purchasing something and the cashier says "swipe your card when you're ready," I get the urge to just stand there, card in hand, and staring at the debit machine. I'd do this until the cashier says "you can swipe your card now." Then I would shout back "I'M NOT READY!"
'Cause, really, that phrase is so stupid. Swipe when you're ready. As if it takes lots of mental preparation or coaching.