I was reminded of a story that I had heard long ago, when I just read it again on a fascinating new blog that I found, http://artofmanliness.com :
A man walking on the beach saw a child reaching down to pick up small objects and then throwing them into the ocean. He called out "Good morning! May I ask what it is that you are doing?" The child looked up and replied, "Throwing starfish into the ocean."
"I must ask, then, why are you throwing starfish into the ocean?" To this, the child replied, "The sun is up and the tide is going out. If I don't throw them in, they'll die."
Upon hearing this, the man commented, "But do you not realize that there are thousands of starfish? You can't possibly make a difference!"
At this, the child bent down, picked up a starfish, and threw it into the ocean. As it met the water, he said, "It made a difference for that one." ~ Adapted from Loren Eiseley "The Star Thrower"
Which reminds me of a favorite Charles Dickens quote, "No one is useless in this world who lightens the burdens of another." Which means that, assisting someone in any need enriches your life and the life of the person that you help, so that both parties have reached their purpose of meaningful existence, together.
More on Joel Barker's wonderful enterpretation of Eiseley's story: http://www.starthrower.com/star_thrower_story_script.htm