Re: Sometimes though....
There was the occasion when, arriving at work in the morning, everything was dead.
All servers down, no printers powered up... the works.
As people drifted in and found that even the kettles weren't working (the biggest disaster imaginable) there were growing murmurings of discontent.
This despite the company having 'acquired' a UPS system the size of 2 shipping containers and enough capacity to keep a small village going -- for a project of 3 servers and around 80 PCs sitting in some outbuildings on the edge of a main site.
Questions were asked. Fingers started to be pointed at facilities management and IT.
Finally, one of the less technical people [ie financial management], with no private life and a desire to come in hours before contracted time, owned up and said "That box in the corner was making a terrible racket so I switched it off" -- of course the 'terrible racket' was the audible alert on the management panel that showed that the UPS had kicked in.
On a separate power loss topic...
I also heard a story (possibly urban myth -- this wasn't from my personal experience) of a demo in the days of FDDI networking - early-mid 90s when people could still remember Sylvester Stallone making Rambo movies.
The vendor wanted to show resilience and 'keep going' features and had one of the fibre cables draped over a tree stump on stage. At a certain cue, an actor rushed on stage with a machete and severed the cable -- and everything kept going. One day however, the cable was not on the stump, so he picked up the nearest one and hacked that -- except it was the power cable, not fibre. Spectacular results, but not too great from a sales presentation point of view :)