It was disability awareness day at a Red Sox home game in Boston's Fenway Park.  A young man with autism sang the national anthem.  Partway through he develops a case of nervous giggles.  At first there's a lot of good natured laughter and it's not clear if he's going to be able to finish the song but when he falters, the entire crowd at Fenway joins in and finishes the song with him.  It's incredibly moving and one comment I saw said something like this:

"I think people in general are bastard coated bastards with bastard filling, but this almost restored my faith in human nature".

I wasn't there, but I'm going to guess what happened.  When the singer began to giggle, while everyone was laughing, one person realized the young man wasn't going to get through the song and to help him, he began to sing along, loud enough that people could hear him.  As people realized someone else was singing, they caught on; "oh yah, we can help this guy!" and suddenly an entire stadium of people does the right thing because someone showed them the way.

One person can make a difference.