Alexander Arvidsson tells a story:
The patient was a misbehaving SQL Server 2014 running in a two-node cluster. It was your garden-variety cluster with a shared disk and a remote witness. In my experience, as long as the customer has enough know-how to maintain a cluster like this, it’s essentially bulletproof.
This specific cluster was not.
Click through for the story, as well as a reminder of why people in mission-critical situations tend to follow checklists and say the items aloud.