" With apologies to the delicate nuances of neuroscience, here is what is happening in a nutshell: Within our brains are billions upon billions of neurons, interconnected in every which way to form a complex set of neural pathways. Electrical currents travel down these pathways, from neuron to neuron, delivering the messages that make up our every thought and action. The more we perform a particular action, the more connections form between the corresponding neurons. (This is the origin of the common phrase “cells that fire together, wire together.”) The stronger this link, the faster the message can travel down the pathway. This is what makes the behavior seem second nature or automatic. "

― Shawn Achor , The Happiness Advantage: The Seven Principles of Positive Psychology That Fuel Success and Performance at Work