My ex-boss just wandered over to brag about a neat piece of machine code hackery he'd just worked out (specifically, single ARM instructions that set the N, Z and C flags to any meaningful combination of values).

I promptly flicked over to my editor window, and opened up a text file I wrote within a month of arriving at ARM (i.e. four and a half years ago) containing exactly the same analysis. Then I showed him the timestamp. He was a bit put out >:->

(Somewhat spookily given there are many equivalent instructions for most possibilities, we turned out to have produced exactly the same table. Evidently I absorbed the ARM groupthink excessively fast…)