There are many ways to answer this question and I don't claim to be the final authority on that subject. However, after helping thousands of students to create more amazing results than they even believed was possible, here's the answer I've come up with. And it's a simple answer, because I've found (and I'm sure you have, too) that the simplest answers usually lead to the best results.
Here is what I have shown to thousands of people in my seminars, and I call it The Scales of Success. Picture a balance, like the scales of Justice you've seen in a courtroom - an instrument for determining weight that has a fulcrum at the center, from each end of which is suspended a plate.
Now, on one plate, I want you to imagine that we have something called Your Why-To's. These are your internal motives or Reasons Why to do something.
On the other plate, we have Your Why-Not-To's. These are your internal Reasons Why Not to do something.
Let me give you an example from your own life. Why are you reading this book right now? The answer to that question is actually very simple. The reason you are still reading this book right now is because you perceive that there are more Why-To's of doing so than Why-Not-To's of doing so in your life right now.
What does that mean, exactly? It means that you perceive that there are more Benefits of reading this book (another word for Why-To's is Benefit) than Costs of reading this book (another word for Why-Not-To's is Cost).
Your mind is like an infinite weighing machine - every moment, your mind is weighing your perceived Benefits against your perceived Cost of doing any behavior or activity you can think of.
Can you also see that every decision we make as human beings is built upon our Why-To's and Why-Not-To's?
* Where you live
* What you wear
* What you eat (and how often you eat it)
* What kind of car you drive
* What you do for work
* Who you decide to marry - or not marry!
* What you had for breakfast this morning...
All of these were determined by your Why-To's and Why-Not-To's. In fact, every decision you've ever made in your life was based on your internal Why-To's and Why-Not-To's: your reasons why you thought you should do the thing vs. the reasons not to do that thing.