I once had extremely difficult clients in front of me acting like the world owed them everything. They yelled at me for things I had absolutely no control over (a flight diversion due to weather), traffic at their destination, and kids running down the hallway of their hotel, and too many people at Disney (they went over Christmas break.... You can't pay me enough to venture there during that time)
I listened, I commiserated, I kept my cool. They left somewhat placated.
As soon as they were out the door, I calmly got up, walked to the back, made sure the door was closed and let loose a barrage of colorful insults peppered with language not safe for work.
My boss happened to have seen everything and had followed me to the back, to make sure I was ok, and therefore he heard every single word of my tirade. As soon as I finished ranting and took a breath to reset myself, he looked at me (who was now calm and collected) and said....
"I've never seen anyone flip a switch so fast in my life. I'm impressed."
So yeah, flipping on and off in the blink of an eye is an ingrained talent.