Islands
As humans (operating in little isolated islands of awareness), it's often hard to believe we have much impact on others, even those we know well and see often.
I was having a very interesting conversation this evening, with a friend with whom I often get into such conversations, because we are both built that way.
He said something to the effect that he thinks he's very selfish because he has trouble remembering things that don't directly affect him. I told him that I don't think he's selfish at all (he's not), and that being selfish is about not being interested in or caring about anybody but oneself, rather than a lack of remembering the details of things other people have told you.
Anyway, that's slightly beside the point. I do think, though, that it's very hard, in some ways, to imagine the world beyond our mental four walls. We all have the George Bailey syndrome to a certain extent.
So I find it interesting that a chalked message on a Portland sidewalk so affected two knitters of that city that they posted photos of it on their respective blogs.

Don't forget one little detail: Portland is magic.