Remarkable Quotes about Startups and project management

There are alot of amazing Entrepreneurs in the World in general in the MENA region, and many of them are great speakers and have been quoted in many articles,books,magazines and newspapers, since such quotes mostly have come out of experience and/or great thinking ,hearing them would beneficial for people considering to start up their own business.

Can you share some of the quotes that affected you the most? (or generally believe are great quotes :) )

My favorites:

"The Best Entrepreneurs Know How To Fail Fast" Or "If your going to fail, Fail fast"

---Don't know who originally said, but 1st time i heard it was by Jon Philips who was quoting Sami al Shalabi (both are amazing personals and Entrepreneurs)---

“Obstacles are things a person sees when he takes his eyes off his goal.”

E. Joseph Cossman

"The critical ingredient is getting off your butt and doing something. It's as simple as that. A lot of people have ideas, but there are few who decide to do something about them now. Not tomorrow. Not next week. But today. The true entrepreneur is a doer, not a dreamer."

- Nolan Bushnell, founder of Atari and Chuck E. Cheese's