Imagine walking down a street, on a minor errand. A man steps out of the crowd and asks you for directions to somewhere nearby. As you explain them, he laughs and calls you by your name. It's your brother. You had no idea, until you heard his laugh. You didn't recognize his face, but you'd know his laugh anywhere.
Imagine looking through photographs of a recent family gathering you attended. There are dozens of people. Even though you were there, you don't know who most of them are. They might as well be from some other family. You're not even sure about photos of yourself, until you remember what you were wearing that day. Each face in the photos is a stranger's.
Imagine that a stranger smiles at you on the train after work. Embarrassed, having nothing to say, worried about why the person is smiling, you look away. What does she want with me, anyway? When you get to your building, the stranger comes up behind you. It's not a stalker, it's your next-door neighbor. You didn't recognize her on the train. At your building, though, her identity is obvious.
Each of these incidents - and many more like it - has happened to me. They are not isolated incidents, they are the story of my life. Welcome to the world of faceblindness. In this world, every face is a stranger's. No matter where you go, you are among people you don't know. Friends, family, co-workers, classmates - if they're not where you usually see them, they are strangers to you.