Streets in modern cities tend to be designed for going through not for staying in. This is reinforced by regulations which make it a crime to loiter, and by streets which are too unattractive or have too heavy traffic to socialize in, so that people are virtually forced into their houses.
In many cases, streets are built to be economically viable for commercial purposes: as straight as possible, without pedestrian paths, and with no trees. Such designs promote the increased use of automobiles and discourage human contact.
Just as for centuries the street provided city dwellers with usable public space right outside their houses, present-day streets should be designed for human contact, and not just for moving through.