Oh my gosh, I just learned this amazing thing.
Suppose I've had an argument with Ted. If it didn't go well or hasn't been resolved, I likely have this annoying pinging in my head that involves worry about how Ted feels about me, and worry that he believes false things about me. The worry is potentially productive, and is directed toward causing Ted to believe true things or to feel about me the way I prefer.
But other people's minds are really hard to control compared to my own mind. So before I reach out to change more distant parts of the world, I should say to myself, "Suppose Ted really does feel or believe exactly what you fear he does. Further, suppose it turns out that no matter what you do, you can't change his mind. How would you like to feel about how he feels about you?"
I've done similar things in the non-social realm (this feels close to "give yourself an escape route" and "bad news is good news"), but somehow I've never applied it to interpersonal conflict.