Sexy Nerd is a mechanical engineer. He knows his cars. However, the AutoZone cashier wasn't so sure, and proceeded to lecture him on being very careful when opening the wrench packaging so he'd be able to return it if it was the wrong size.
Sexy Nerd: Don't worry. It's the right one.
Cashier: I'd better look it up, just in case.
Sexy Nerd: That's okay. I know this is the one I need.
Cashier: No, no. I'll just take a quick look. What kind of car is it?
Sexy Nerd: It's a 2013 Chevy Volt.
Cashier: (...awkward pause...) Is that a car?
(...more moments of awkwardness...)
Oh! Is that one of those electrical ones?
How much did that cost you?
The Volt actually only costs about as much as a Prius, but I wish Sexy Nerd had replied "a hundred grand," just to see the look on the guy's face.