At one time (about ~3 years into lifting), I was probably one of the "strictest" most straight edge lifters you could find-- in regards to trying to do everything as "optimally" as possible.
I followed my training to a T-- no more, no less. I did exactly as my coach instructed, and would spend any free mental space thinking about my training, technique, etc. Constantly looking for ways to be better.
Now, I truly believe that that level of discipline early on was for the better. It allowed me to practice extreme discipline with my training, it gave me the time to really experience and learn from the various training implements/programming/etc. that my coach experimented with, and it allowed me time to learn how to become a student of the sport. It was the time to "shut up and listen".
Today, I am still by no means a "veteran" of powerlifting-- about ~5 years in, I still have much to learn and experience. However, I do a lot more "coloring outside the lines" than I did before-- and I believe I'm better for it.