I always find it surprising how often items meant to ensure business continuity are the cause of business "in-continuity".
From a Raid system borking, to a HA a pair corrupting data as it tried to switch over, to a DR site not coming on line properly during a test or an Active/Passive pair turning into Active/Active unintentionally and creating their independent two sets of data.
I ran a Netware server for about 12 years, with a single power supply and non-Raid with no loss of data. Even cloud services have given me more time out in recent times.
P.S. I'm not saying we should all switch back to single unprotected servers, btw.