I tend to emotionally detach as a protective response, likely from my upbringing. I see someone losing control over their behavior due to their own emotional responses, and I know nothing will get solved if everyone's losing their shit. Or, depending on the situation, the person [this has only happened with unhealthy people, though] might be yelling in an attempt to draw out an emotional response from me, to feel a sense of control over the situation, because, as noted above- when someone's already yelling, they've lost control-- some people NEI'm ED you to react in a similar, volatile way in order to feel emotionally validated. That said, I can't allow myself to give them the satisfaction of upsetting me, nor can I in good conscience feed into an unhealthy dynamic like that. The behaviors people resort to, when expressing their anger, on some level, ARE a choice, and over the years I've made it my choice not to allow their problem to become mine on that basic level, and create needless stress.
I mean, sure, if it's someone I'm close to, of course I am anxious and stressed because they're angry with me-- I can't stand that--- but I still tend to shut off emotionally until things are calm. Kind of figure if they've gotten that upset, communication has already broken down, or it's not possible to attempt to communicate when they're that revved up in the first place, though I may stand there and ''actively'' listen, til they get it out of their system-- depending on the situation. I'm more than happy to discuss & hopefully clear up whatever upset them when they can remain calm; I don't hold their initial reactions against them, per se- I just don't allow it to upset me in the moment. Some people may disagree with me on this, but in everyday situations, I seriously see no reason to YELL about anything. It's just an assault on everyone around you, and in of itself resolves nothing.