Watching a user test your product for the first time...

You turn the handle and walk through the door

Sat my non tech office mates down in front of a simple service where drop down 1 makes drop down 2 display available choices. Then push the button to display the hits. Lets just say there was more room for clarification than I thought :)

In my former job we used to ask the sale assistants (who didn't know anything else than excel) to test our deployement processes. We called it "The Donkey Test".