Biting one’s tongue around literal thinkers.
I was talking with a fellow last weak about a gear train on some equipment that was meant to run dry. He asked if there was any benefit to greasing the gears anyway. I suggested that any oil or grease would only serve to let dust stick to the gears and wear them down quickly; something I’ve encountered in conveyor drives.
I would normally have said something like, “It’s made to last a lifetime but if you grease it regularly it should last about 7 weeks longer.” The problem is I didn’t know this guy too well and had the impression he tended to think literally. I was worried that in saying that to someone who thinks in absolute terms, they might interpret the joke as validating the suggestion to lubricate. Seven weeks longer is longer, after all.