I've seen this happen where one person enjoys debate/arguing and another does not. To one person it's an interesting discussion, and to the other it feels like a personal attack. Or, more commonly, I've seen onlookers get upset watching such a discussion, even if they don't personally feel targeted. Specifically, I'm remembering three men loudly debating about physics while several of their wives left the room in protest because it felt too argumentative to them.
Body language and voice dynamics can affect this a lot, I think - some people get loud and frowny when they're excited/thinking hard, and others may misread that as angry.
I ended up having to include a disclaimer in the FAQ for an older project of mine, saying that the senior staff tends to get very intense when discussing the project and that this doesn't indicate drama on our part but is actually friendly behavior. That was a text channel, though, so body dynamics and voice wouldn't have had anything to do with it. I think a lot of people just read any intense discussion as hostile, and quality of argument doesn't really enter into it -- probably because they're used to an arguments-as-soldiers perspective.
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