services

Each type builds on the one before it rather than replacing it. Saying that out loud is the whole answer, and it also explains why a LoadBalancer costs money and a ClusterIP does not.

Kubernetes has no concept of one object containing another. Everything that looks like ownership is a label query evaluated continuously, which explains both how Services work and how a typo silently empties one.

This one separates people who read journals from people who restart harder. The exit code and signal systemd already recorded usually name the disease.