Controlling people with emotion

Emotions can over ride the rational thought process, we are all guilty of this from time to time mainly as "impulse buying". Though impulse buying is the simplest form of an emotional over ride, the process of controlling a person with emotion is basically the same concept. When you use certain key words or phrases you can instill an emotional response in someone, you can, given enough time, manipulate that person into believing what you want them to believe, think & even say. Once people start to think with ego/emotion there is no need for verifiable facts simply because a persons ego steps in & makes them ignore truth for fear of being wrong.