Too easy done (worst one I've ever done was at work had mulitple applications open, doing some forecast analysis (what if we did this type stuff) closed and saved my spreadsheet or so I thought, I'd changed a data model containing our product release forecast data, the system automatically emailed 500 people to tell them I'd changed the release data etc etc. I had to write a special piece of code to unwind the changes and tell everyone that I'd done it. (How embarrassing is that for an IT manager???)

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