I believe the Wal-Mart greeter programme was started as a way to provide gainful employment for seniors (although, as with all things Wal-Mart, extreme skepticism is warranted as to their true intentions). For an alternative explanation, see the Wikipedia entry: https://en.wikipedia.org/wiki/Walmart_greeter Many of the differences between British high-context, implicit culture and American low-context explicit culture stem from the latter's need to integrate vast numbers of immigrants, many of whom did not speak English as a first language. Darwin originated something known as the Facial Feedback Hypothesis, that forcing yourself to smile actually improves your mood, and there is some experimental evidence supporting the theory. If the British smiled more as the Americans do, perhaps they would be less happier and have a sunnier outlook on life, miserable weather notwithstanding.