What motivates us to do the things that we do? Why do we think and behave as we do? What influences people to do what they do? The word "motivation" means different things to different people. One thing for sure is that you can't buy a jar of it: it has to come from within yourself. A person's brain needs constant motivational input just as muscles need exercise, engines need petrol and plants need water. I used to think that motivation was a slick American fad and that it wasn't for me. After.