[mitchs]

> "all observable behaviors of your system will be depended on by somebody"

Ugh, a former team I was on had that to the extreme. We were customizing open source software for internal use. A lot of operators had (over years) developed scripts that would just SSH in and use a CLI to interact with the software, using regex to parse output. We once thought we were safe adding a new line to the output rather than modifying an existing output line. Nope, someone somewhere used a multi-line regex.

Kicking everyone's automation out of the shells of those boxes was a multi-year project that is, as far as I know, still ongoing.