I had one situation where a Hetzner dedi didn't come back up on a reboot. Their dedis are cheap, this one is like $40ish/mo?

Opened a ticket and support had it back up again within about 10 minutes, turned out to be a failed CPU fan which caused an overheat condition and made it so the system wouldn't complete the boot. They swapped the fan and it came up. It's the only failure I've had in years of dealing with them and was just impressed how quickly a physical failure event like that got handled.