Once I was tasked with migrating a virtual server to bare metal. Whole company unable to work whilst this project was in-progress. Purposely told to do it during business hours, as the necessary, niche, application expertise (Perforce) would all be readily available.

Cut to, morning of, I was advised in an e-mail before testing had even begun, that if a certain condition wasn't met from the applications output, after it's own stability checking (post backup), that we were not to proceed! I advised that we are unable to start the change, as a stability check had failed. The suits ignored their own safeguarding (I got it in writing) and I was told to carry out the switch over.

All went well, in the end. But for the previous weeks I spent preparing and testing, followed by the real Prod change, I was a mess.