We do it all the time.
Ritual greetings are useful, and a custom ages old.
But one of the logical consequences of this one that we tend to believe it. And so we walk about everyday in a world full of people busily going about everyday business looking normal, unruffled and mostly content. And we assume they are , and that few of their lives are touched by wonder, mystery, tragedy, anguish or terror. But none of us who survive have survived unscarred. Pause a moment and scan your skin.