There were a lot of things to learn at my first job.  My boss, Len, seemed to have a lesson for me:

I had designed a circuit for a pump and sent it through “the system” to be detailed.  When the detailed drawings came back, my boss brought it to me and told me that this was not the way we did this.  He marked up a drawing to have me change it. Ok, his way worked as well as mine, so I redid the circuit and sent it through the system again.

When the new drawings came back my boss came to me again.  He said that this was not the way we do this and marked up my drawing again, putting it right back the way I originally had done it.  Luckily, I had placed his initial markup in my desk drawer and pulled it out to show him.

He never did that to me again.