At the age of twelve I first worked on farms near home on the edge of suburbia. There I learnt to greet anyone when I met them for the first time in the day with Good Morning or Good Afternoon. If I encountered the person later that day a nod of the head or a smile of recognition would be enough. This was never explained to me: it would have been bad manners to explain the requirements of good manners, a presumption that the person addressed could not understand their importance.
Recently a neighbour was walking his two dogs along the sea-wall. The path was narrow so that when two people were about to pass one another in opposite directions, one of them would have to stand aside. A couple approached with two dogs in tow and he paused, ready to step to one side, which he did. Without a word, without a glance in his direction, without a gesture they brushed by within inches of him, their only apparent concern being not to tangle their dogs’ leads with those of his dogs. Like a skier who sees a space through which to slip by without interruption, or an impatient motorist who detects the slightest hesitation on your part, they had passed him by.
He might as well not have been there.
Had the couple been lost, had one of their dogs gone astray, had one of them been hurt or taken ill they would have acknowledged my friend at the very least as they asked for help. This is natural; this makes sense for when we are in trouble or in difficulty it is to other people that we turn. Down the ages we have learned to turn to other people when building pyramids, or hunting mammoths, or in childbirth, or learning a new skill, or growing food, for encouragement or when defending ourselves from our enemies.
However much we try to be self-reliant and not burden others there are times when we need other people, not only in an emergency but as part of an assurance that there are others who will help us, and, of course, who may need our help at times.
That is why we exchange a smile, or lift a hand or call out a greeting, to acknowledge our common humanity.