What Keeps You Motivated

What's the source of your inspiration?
Your thirst for success, your drive to pursue your goals, the root of your focus?
That's assuming you have one.
Are there phrases, words, quotes, memories of lost loved ones, etc,  that keep you motivated?
What is/are the most influential word(s) you've ever read, or heard.

Remember,
"Don't let the fear of the time it will take to accomplish something stand in the way of your doing it. The time will pass anyway; we might just as well put that passing time to the best possible use."
~ Earl Nightingale