"He's doing his homework"

I was taking a break from the stress and strains of working for a multinational company today by doing some reviewing for an international research conference in a nearby coffee shop. While wrestling with a particularly complex mathematical proof, a small child ran up to my chair, and started staring at my fevered computations.

"Leave him alone," the yearling's mother said, "he's doing his homework."

Well, that put me in my place.