Once came back to work after 4 week holidays (not USA) and realized I forgot the 3 digit code to my locker.

But I remembered that friend's locker (he was on holidays then) used US police code for murder. (Police in US use codes for crimes when communicating on the radio).

I googled the code, used friend's locker for the day, and by lunch the next day I've bruteforced through enough codes to learn that my code was the embarrassing 420.