E.M. Forster said the only really important thing is to connect with other people. I've had my share of wordless retail transactions (and hell, relationships, for that matter), meetings where I didn't really even say hello to the people in the room before launching into the agenda, entire meals with people where the only sound is the scraping of silverware on porcelain. With connection comes responsibility and accountability. Sometimes we welcome that and sometimes we avoid it. If you ask someone how they're doing, the answer might not be good, and what then? You'll probably be late for something.
When I run, I look down at about a 45-degree angle. This covers the range of possible hazards: other pedestrians, cars, things to trip on. I might fall over, but I'm going to try and look up more.