I built a system at an old job that as far as I know has been in operation for over 10 years, completely untouched. I left the company that long ago, interviewe

I built a system at an old job that as far as I know has been in operation for over 10 years, completely untouched. I left the company that long ago, interviewed about three years ago for another position in the same department, where someone disclosed it was still up and running, without modification. I’m sure someone had to read the code at some point, but they could have fired me right after it was built and suffered no great loss because of it. I guess I should’ve spent some more time overengineering the whole thing or introducing subtle bugs if I wanted job security, as I have seen others do.