I once had a classified ad software hustle, and I needed customer data to debug things. But one of my customers was Canada's largest gay newspaper, and ts classifieds were highly sensitive.
So I wrote a routine that obfuscated the database, changing all phone numbers to 555-xxxx, changing all names to random names of fruit (So a customer might become Banana Grapes, 416-555-1234), and a few other changes to hide other possibly identifiable information.
I had a menu item to do that to the database, it was under a "developer" menu that only appeared when I was personally signed in as the only superuser. I am embarrassed to say the menu item was called "mixed fruit."
One day, I was signed in at the client's office, and the manager came by and wanted to do something or other. I gave him the mouse and keyboard without logging out and asking him to log back in. He did his job, then noticed the developer menu. "What's this," he murmured, and selected "mixed fruit."
No confirmation dialog, no warning, it begin munging the live, production database as I watched in horror. I managed to get everything sorted and the production data restored, but I learned a few lessons that day about building super-features for myself that were extremely sharp and difficult to undo.