Never in my experience when someone says it just works does it just work in reality. Usually they are hiding some things that they are keeping up with but for some reason don't include those issues as the thing not working.
I look after a lot of k8s professionally (hundreds of clusters), and the only issues I've had in the last few years were a istio/pilotd bug and a bit of pain moving from e.g v1beta1->v1 during normal upgrades.
Everything else that's gone wrong with these environments was cloud/hw related, or app stuff.
