Abbreviated and paraphrased version of a support call over 30 years ago (I've probably recounted this before on here):
User: "It's completely dead!"
Me: "Have you checked the power lead?"
Me: "Can you unplug the power lead and plug it back in, making sure it's properly in?"
User: "Yes, I've done that - it's still dead!"
Me: "OK, I'll call an engineer but if they don't find a fault it will be chargeable."
Engineer: "I've plugged the power lead in properly."
IBM Service (to User's boss): "Here's the call out invoice!"
User's Boss: "*&())*&%$("