I asked a person I once met how he became so skilled at staying calm under pressure. He said, "I pretend that everything that happens is on a large video screen. Every person I interact with is part of the scenery. I'm the only person that is alive and real; everyone and everything else is just what I see on the screen of my mind.
"My choices of thoughts, words, and actions are like a game I am playing on the screen. I always maintain self-respect and respect for others, but nothing anyone says or does will intimidate me.
"If someone raises his voice and yells at me, I imagine the clown on the screen acting like he has lost his temper. I don't have to worry as long as I'm not in physical danger.
"I keep asking myself, ‘What would be the wisest thing for me to think, say, and do now?' Because I keep calm, I am able to think more objectively."
(From Rabbi Zelig Pliskin's book: "Building Your Self-image and the Self-image of Others" (Artscroll) Chapter 75)