How we change what others think, feel, believe and do
Emotion and Rationality
Emotion and rational thinking are, to a certain extent, mutually exclusive.
When we get emotional about something, our ability to make rational decisions (which we will look back on and agree are good decisions) has a strong tendency to fail.
Consider the things we say. A person who is 'hot-headed' is considered to be rather emotional and likely to make rash decisions, whilst a person with a 'cool head' makes thoughtful, considered decisions. We talk about mental processes being 'clouded' by emotional states.
Emotion is a chemical state in our brains which we experience as basic 'feelings'. Those same chemicals inhibit our higher cognitive capabilities and limiting what we call rational thought.
The effect increases as emotional arousal increases. Think of the ardent lovers who have married in haste, only to repent at leisure (Las Vegas seems to do this to people more than most people -- but then Las Vegas is designed to stir the emotions).
The same is true when a person is frightened, and the Fight-or-Flight reaction gives them the ability to fight for their lives. Many homicides are committed whilst the perpetrator is an extremely angry state. Temporary insanity is a not uncommon plea, as the extreme emotion literally makes the person unable to make any socially acceptable decisions.
If you want someone to make a rational decision and they are in an emotional state, then help them calm down (but do not just say 'calm down', which is a rational appeal). Speak to the emotions with emotional words and then slowly become less emotional. If you have time, the simplest approach is just to wait. Emotions do not last and the person will eventually cool down.
If you want the other person not to think about the decision, then get them into an emotional state. A sales person will get their customers excited, hopeful or into a state of lust. Politicians will invoke fear or the desire to help their fellow humans.