My personal favourite, this woman phones up in a panic...
Her: "I'm just about to go into a meeting crucial to a new multi-million pound deal, and the Powerpoint presentation I need has disappeared from my laptop!"
Me: "When did you last see the presentation on your laptop?"
Her: "Well, that'd be last night, just before I let my 4 year old daughter have a go on my laptop".
Me: "Okay..."
No shit