Face blindness:

"I've had difficulty recognizing faces for as long as I can remember," Sacks said.

Every face looks pretty much like every other face. It's called face blindness, or prosopagnosia.

"I can see your expressions and your attention and where your eyes look. I see all the features but it doesn't quite add up to a unique image."

Someone who is face blind sees the features, but can't place the face.

"Sometimes I kiss or embrace strangers thinking that I know them," Sacks said.

Gosh, wouldn't that be embarrassing if i kissed the wrong Michael Keaton?