Devops; being able to stand up your entire stack in an automated way. Some programmers dismiss this as "yaml/bash engineering", and that's true, but it also challenges all of your assumptions in your stack. If you can't stand up a complete duplicate programmatically, you almost certainly have implicit assumptions that you haven't verified, which will make it much harder to recover from disaster or scale.

Put another way, devops is a mix of declarative programming (YAML) and writing idempotent, imperative code in the presence of large side effects (bash). Learning to handle both is very educational.