When I think about neighbors, I think about density. That's likely because my work includes occasionally travelling the world talking about great city-building, including what I call "density done well."
I discuss all the public interest benefits of smart densification in cities, designing for more people on less land using less resources, from lowering our carbon footprint and increasing our energy resiliency, to making walking, biking and transit more inviting, improving our public health, and avoiding the bankrupting economic costs of sprawl.
However, my favorite way of thinking about density is by looking at people. Putting more people together in beautifully designed neighborhoods and places, supports everything that makes us human, from creativity, tolerance, and happiness—to even sexiness!