Why Visualization is important to achieving goals?

I am reading an ebook called "Goal Setting Secrets" which is about setting goals and achieving them in life.

One of the most important thing to achieving goals in life is to visual the end-state. It basically means visualizing yourself achieving your goals, getting what you wanted and seeing yourself in that state where it is achieved.

It can be a thrilling experience to imagine and see yourself achieving what you wanted at first, and then pretty boring and mundane as you carry on this excerise by yourself later as time goes by and you don't see it really materializing in life.

However, this is where most people fails to realize the power of visualization. As the visualization gets blurry, so does your attraction to materializing it! Here's a great analogy from the eBook that I was reading:

If you were watching television and the picture became fuzzy and difficult to see, you’d first try to fix it. However, if the picture remained fuzzy, you’d change the channel, regardless of how much you wanted to watch that particular program. Without the ability to see it, you’d have little if any interest in it.

Without a strong focus on what we really want, then we will soon lose the drive and energy to achieve what we really want.