Are you breathing?
Many times we respond (or react) far too quickly when it comes to our Difficult Person. The tension is high, it has become personal, and even though we often know better, we are quick to respond to a situation.
The next time you are dealing with difficult people, remind yourself to breathe! Before you say anything, before you do anything, before you continue, take a deep cleansing breath.
It might not completely protect you from responding the wrong way, but it will buy you those precious few seconds where you can remember to bite your tongue, or follow your strategic action plan (and just might save you from saying something you will regret).