When it comes to tough negotiations any little edge you can get is a plus. Successful negotiators
know that it is often the small, unconscious signals and cues that can influence your outcome in a positive way.
When someone is saying something or behaving in a way we don't like, we often make the mistake of looking them straight in the eye, which can create a more confrontational environment.
Instead of looking them in the eyes look at the bridge of their nose. It won't get their back up the same as looking them in the eyes might, but it will prove unsettling to them and will often lead them to drop their eye contact and stop their rant.
It may take a little practice but it can serve to help stop a tirade or to undermine a power play.