Coworker*: [looking at ruler]”Wow, I had no idea that there was about two and a half centimeters per inch.”
Me: “Actually, there is exactly 2.54 centimeters per inch, by definition.”
Coworker: [glares sharply at me, then attacks me with ruler]
* Coworker at my day job (doing IT for a university department). He’s not really a science/math type.