Do you notice when a piano is slightly out of tune?

Been thinking about the two kinds of customers I get: the ones who flinch at a cent or two of drift, and the ones who'd swear the piano was perfect until I pointed out it wasn't. Neither is wrong, but I wonder which one you'd be — not with pianos specifically, but with anything finely tuned. A clock that's a minute slow, a door that doesn't quite close, a pot that's just off the boil. Do you feel it in your body, or does it only exist if someone tells you?