Nothing great was ever achieved without enthusiasm. The way of life is wonderful; it is by abandonment.  (Ralph Emerson)

It is not necessary to do extraordinary things to get extraordinary results. (Warren Buffet) 

The real secret of success is enthusiasm, I would say excitement. ( Walter Chrysler)

When you really believe in what you are doing, you must persevere despite all obstacles.
 
You can't help someone uphill without getting closer to the top yourself. (Proverb)

Do something. Either lead, follow, or get out of the way. (Edgar Shalton)

The time when you need to do something is when no one else is willing to do it, when people are saying it can't be done. (Mary Berry)

It is the greatest of mistakes to do nothing because you can only do a little. (Sydney Smith)

It is the action, not the fruit of the action, that is important. You have to do the right thing. It may not be in your power, may not be in your time, that there will be any fruit. But that doesn't mean you stop doing the right thing. You may never know what results from your action. But if you do nothing, there will be no results. (Mahatma Gandhi)

There are those who share their talents and make money, and those who are incredibly talented but take those talents to their grave-poor. I want to know what are you going to do with what you know? 

Life is like a boomerang.  What you give out you get back.