While between two IT jobs, I spent several months working behind the bar at a local pub. (I put this down as "acquiring good customer-facing skills" on my CV, though most software engineering roles do not require evicting agressive, drunk clients from the building.)
One busy weekend, some of the bar staff failed to turn up, and the landlord tried to ring other temporary staff. After quarter of an hour receiving "number unobtainable" responses, he thrust a mobile phone and a notebook into my hands and said, "Keep ringing these numbers until the lazy ****s answer!"
I replied, "Er, boss, these aren't telephone or mobile phone numbers. They're National Insurance [social security] numbers."