@nevali especially good one, but device-specific...
someone not-me built a server.
set up windows server 20xx on it.
used the serial number on the box as the admin pwd.
then racked the server, with appropriately lengthed network and power cables, into the 2u hole left for it.
tried to domain-join it, hadn't recorded the pwd anywhere because *on the box anyway*
on the top lid of the server. which was now halfway down a production rack with powe lr cables too short to roll it out on the rails.