Great example came in today. Someone had a Dell server, four matching drives. The system arrived with no virtualization configured and the OS was installed without RAID on a single drive. Each drive was attached as an individual drive. Obviously Dell never intended someone to use the system like that, even for a desktop that's not an acceptable setup. It's pretty clear that it was just a test install to show that the hardware was working.
But several people said "but Dell set it up this way, obviously it is okay" and it has been running in production and is now a disaster.