While walking along the beach, a man saw someone in the distance leaning down, picking something up, and throwing it into the ocean. As he came closer, he saw thousands of starfish the tide had thrown onto the beach. Unable to return to the ocean during the low tide, the starfish were dying. He observed a young man picking up the starfish one by one and throwing them back into the water. After watching the seemingly futile effort, the observer said, "There must be thousands of starfish on this beach. It would be impossible for you to get all of them. There are simply too many. You can't possibly save enough to make a difference." The young man smiled as he continued to pick up another starfish and toss it back into the ocean. "It made a difference to that one," he replied.
"There is a terrible forest fire. All the animals are fleeing the conflagration except Hummingbird, who is flying back and forth, scooping up little slivers of water from a spring and dumping them on the flames. 'What do you think you're doing, stupid little bird?' the other animals ask derisively, and Hummingbird says, 'I'm doing what I can"
--Wangari Maathai, Nobel Prize-winning founder of Kenya's Greenbelt Movement
(Thanks to Terry Clark for these, and so may other great quotes!)