Appropriate workloads for Kubernetes

I've been asked about hosting cloud applications in Kubernetes. People seem to assume that Kubernetes is the best practice for hosting containerized workloads in all cases. While I love Kubernetes and have used it successfully in numerous applications, It shouldn't be the default, out-of-hand, hosting solution for containerized workloads. 

Kubernetes is far from the simplest solution for hosting containerized workloads. Even with cloud vendors making Kubernetes clusters more integrated and easier...