If your web project is focused on a wide audience of modern Internet users, it is not enough to make it good, convenient and popular. The site should also be atmospheric! The atmosphere can be transmitted in different ways, one of which is, in principle, such an occasionally insignificant thing as an error page. Moreover, if the 404 error pages are still 
paying attention , then the pages informing about the inaccessibility of the site are rarely distinguished by 
intelligence and ingenuity informative.
For example, the popular twitter-client 
HootSuite , which for some reason 
doesn’t say a word on Habré, considers that it may not be available on December 23, 2012, and informs about it on its stub page as one of the possible reasons for downtime:

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On our startup 
ProkatVsego, we also tried to add a bit of atmosphericity to the 
404 error page , but unfortunately we haven't reached the rest of the pages yet. And what error pages / stubs do you do?