It's about a guy that knows better.

I was working as a subcontractor on a bigger system. We (subs) were not allowed to deploy code, we had to wait for contractor to deploy.

One day I got an email that my code is bugged and that my feature is not working on production. I checked it on test env, everything was fine. Then I checked if the code I wrote was deployed. It was not.

I send an email explaining that if they deployed my code it would be working. Then I got a response. There was a bug in my code.

Another email. I asked how would they know? Do they have a test on their environment that failed?

No. There is one guy that READ my code and he said it should not work, so he will not deploy it. He was not a programmer, he was a business consultant responsible for the documentation.

His issue was that I used a function that was not in a class. So if the function is not declared it's obvious it will not work. I had to explain to him in another email, that you can use object of another class inside your class and then call a function, that is not in your class. It was the last time this guy blocked my deploy.

TL;DR, I had to explain a non-dev how object composition works in order to have my code deployed. Took four emails.