a difference

One day after a large storm, tens of thousands of 
starfish were washed up on the beach above the 
high tide line. An old man was casually 
wandering  along the beach picking up the 
creatures and placing them back in the ocean. 
A young boy, upon witnessing this occurring for 
some time, approached the old man. 
"Hey Mister, Do you know how many starfish there are
on this beach?" inquired the boy. "I dunno..maybe 
20,000. Maybe a lot more," replied the old man. 
"Why are you doing it then? You can't 
make a difference." The man looked down at 
the starfish in his hand and then up to the boy.
As he placed the animal back into the ocean
he said softly, "I reckon it makes a pretty big 
difference to this one." 
The boy began helping. 

-author unknown