"Because I say so" is a terrible way to communicate why a thing is being done. In senior positions it is definitely necessary now and again to pull rank and tell people something is being done despite their protests, but I don't think I've ever found a situation where I couldn't articulate why that decision had been made. People may disagree with that decision, hell, sometimes I've disagreed with the decision I'm communicating, but you owe it to your people to communicate the reasons.

I had a situation recently where I had a report argue with me constantly over team agreement stuff like code standards and unit test coverage.

I explained every piece of rationale I could come up with for why the team chose to do things the way they did. I offered to schedule team discussions for her to try and convince the team to adopt other strategies, with the understanding that if the team didn't want to do things her way that would be the end of the discussion.

It wasn't the end of the discussion for her though, she kept complaining. Eventually I just had to say "that's the way we do things here so you have to get on board". It's awfully close to "because I said so", and I hated saying it, but I exhausted every other avenue I could think of.

She wound up giving her notice, so I guess we were on the same page because I was working with my manager on letting her go. But if she had been able to keep her head down and do the work we would have kept her for sure. She was a good coder, good systems knowledge, just really didn't like writing unit tests I guess.

Yes but you already gave plenty of reasons before resorting to "that's the way we do things". And I think that's fine. What wouldn't have been fine would have been to skip the explanations.

Most people, given explanations, will accept them even if they don't agree with them. And quite often they will realize that there is more to the issue than they originally thought.

Fully agree on giving reasons. And more often than not there is room to discuss them. Also, from time to time, it doesn't matter weather or not we agree with those. And then there are those moments were there is no time to discuss.

Good leaders know to tell those appart, and professionals can accept it. Unfortunately, this combination, good leaders being in charge of professionals, is rarer then I'd prefer.

Too rare but when you get it, it's gold baby

Solid, 24 carat gold.