If you find yourself approaching a flash-point try this:
Ask yourself how you’d like the next few minutes of your life to be remembered. If someone was making a documentary what would the fly-on-the-wall witness as it watched you reacting to the stress? Can you choose how to behave in a way that would make you proud when you watch the documentary later?
I discovered this a few years ago and it works beautifully as a way to pull myself back from the brink (on a good day, with the wind behind me).