I have made a ton of mistakes for sure. But at almost every place I've worked, under-engineering has been a much more pervasive problem than over-engineering. A

I have made a ton of mistakes for sure. But at almost every place I've worked, under-engineering has been a much more pervasive problem than over-engineering. And so over-engineering is often used as an excuse not to do engineering to begin with. Building a Rube Goldberg machine to solve a simple problem, or reinventing the wheel poorly isn't over-engineering -- it's just bad engineering. That said, a term I do agree with is YAGNI, which I think is much more concrete and well defined.