I thought based on your opening sentence that you were going to say having no understanding of the problem worked out okay. So are you saying you were unproductive at your old job?
In the beginning, I was definitely not productive at tuning or making changes to a PID loop. Over time, I learned via looking at the code, reading online, and getting training from very experienced automation software engineers. I'm by no means an expert now, but we were able to turn changes around in minutes and be confident in the outcome, instead of hours/days with some doubt as to what would actually happen in the physical world.