One of the most important things I've read is the post Conversational Cultures: Combat vs Nurture.
A very short summary: "combat culture" is typified by people being willing to disagree with each other verbally. "Nurture culture" is typified by people affirming each other and interpreting direct criticism or disagreement as an attack.
I would recommend reading the post, but I'm not writing this post to convince you to read it, more to get out some thoughts on the effective communication.
My stance: not neutral
I've been practicing combat culture communication my whole career, and it seems obviously better than nurture culture.
I want to work with people who care more about their work than they care about their ego, or being superficially aligned during a conversation.
We're here to figure out Truth – I don't really trust my ideas until someone I really trust has tried to argue with them. Working solo is a disadvantage because I don't get that check. Working within nurture culture is the worst case, because even though I can tell my ideas to people, nobody will tell me if they disagree with me, and as a result I feel like nobody is listening to me.
I do disagree with the post's author when they say that countersignalling (the sort of friendly insulting that often happens between friends) has any place in effective combat culture – productive arguments are about ideas and any hint of insulting, even as a joke, tends to get ego involved when it shouldn't be.
Tangent: I don't like the names
"Nurture Culture" isn't a terrible name for the concept I suppose (though it can be very toxic and I personally find combat culture to be nurturing), but I really dislike the name "Combat Culture".
I haven't come up with a label that I like better, though. Let me know if think of one.
I dislike the implication that effective communication between people willing to disagree with each other has anything to do with fighting.
What is effective combat culture?
Ineffective combat culture just looks like two people arguing without really listening to each other.
Mid-level combat culture still looks like an argument, but without the frustration.
The better the speakers are at combat culture arguments, the more clearly they will talk about the assertions being made, and the quicker they update their position when their counterparty makes a valid argument.
At higher levels it doesn't even look like an argument, it's just 2+ people having a discussion and quickly figuring out the Most Correct direction forward, as far as their human reason and experience are capable of. This post is a good description of the combat-culture-effectiveness spectrum.
Does combat culture make you disagreeable?
It doesn't have to. Some of my favorite people to argue with have been very personable and gracious.
I aspire to be like them. Yes, it's true that I care more about doing a good job than I care about my coworker's feelings, but that doesn't mean that I can't be a blessing to them while we're doing good work.
The people I've worked with who cared the most about doing the best job possible, and were willing to argue with me when they thought I was wrong, have tended to be the ones I most wanted to be friends with.