Millions of words and only six emotions
The intellectual part of the human mind can spin delightful or frightening stories, can compare features and benefits, can create narratives that compel us to take action.
But all of these words are merely costumes for the six emotions built deep in our primordial soup:
Anger, disgust, fear, happiness, sadness and surprise.
Being angry at a driver who cuts you off in traffic is chemically similar to being angry to a relative who cuts you out of his will. We tell ourselves different stories (the traffic story will probably not last nearly as long in the echoes of our consciousness as the bitterness of the bequest story, for example), but still, there are only six buttons being pressed.
Knowing that there are only a few keys on the keyboard doesn't make it easier to write a pop hit or a great novel, but it's a start. In the case of someone with an idea to spread or a product to sell, knowing that you've only got six buttons might help focus your energy.