A few years ago, part of my job involved keeping a commonly-shared Excel spreadsheet updated with test cases and test outcomes.
One day I decided to hide some of the columns temporarily. I forgot to “unhide” them, then I saved the spreadsheet. Dumb mistake, but no big deal, right?
Client: DID YOU DELETE THOSE COLUMNS FROM THE SPREADSHEET?
Me: Oh! No, but I DID hide them and accidentally saved the spreadsheet that way. Sorry about that.
Client: Sorry? SORRY? Have you any idea what you’ve done?
Me: …but …it’s not that big a deal, is it?
Client: (looking like he wants to hit me) Are you joking? We’ve lost all that work!
Me: The data isn’t lost – it’s just hidden.
Boss: What are you talking about?
I un-hid the columns. The client stomped away without another word.