Why does proximity seem to promote relationships between people?

Proximity seems to promote relationships between people because it brings people together; it promotes familiarity between people because they are often next to each other, spending quality time together. As a famous saying goes, 'Out of sight, out of mind,' meaning that the farther we are from some people, we might be likely to grow more distant from them. This is why it is important to have personal contact with people we care about.