All our thoughts are initiated and mediated by biochemical responses.
Corporations pay millions of dollars to be told how to evoke the responses they want.
Doing this is called 'being on code'.
The most negative word in the world is 'no' and the most positive is 'free'.
(However 'no' can evoke a wanted response when the goal is fear and anger, as in 'No Medicare cuts!'.)
I intuited this biochemistry when I was a child, more than 65 years ago. In the early 1980's, while living on Crete, I wrote a theoretical book The Biochemistry of Moods and Emotions that would have been published by Norton, but the finished manuscript was lost on Crete in my Cold War dust-up with the terrorist organization N17. (Unrevealed investigative reporters are not a good actuarial risk!)
The biochemistry of moods and emotions is now totally accepted by science, but I would still be booed off podia as I was almost fifty years ago at Washington University for this construct:
The Genetic Imperative to multiply to the maximum is the engine of evolution. Every species has evolved its own strategies to multiply to the maxim. History shows that humankind's strategy is competition to the death, winner take all. This explains the human obsession with weapons and passion for war, and why war so often involves rape and genocide.
(See publisher correspondence below.)