Take this sign, for instance. Nothing exciting about the font. Old, fairly ugly building. Nondescript street. But, I'm drawn to it. I think it's because of the negative space above it. The closed-in, concrete ugliness gives way to open, beautiful expanse of sky. And that beautiful expanse seems to make what's under it more attractive.
Digital Field Guide: read a couple of pages in Niki's manual.
Images: one of my iPhoneography groups on Flickr