When you’re dealing with a high-stress situation (e.g., your boss or a client is yelling at you), your stress hormones run amok, causing you to quickly lose perspective. You put yourself at the center of your own world, and you feel threatened and betrayed.
To counteract this tendency, get into empathy and stay there: however difficult the other person is being, work hard to put yourself in their shoes and understand why they’re acting the way they’re acting. As counterintuitive as it may seem, this is the best way to deal with difficult people — it may feel like doing them a favor or excusing poor behavior, but it actually makes you less reactive and more effective. This doesn’t mean you should justify their behavior, but you should understand it — and often what looks like a character flaw is really a situational problem.
By doing this, you’re re-centering yourself and gaining the perspective you need to de-escalate and handle the situation properly.