If you have only one smile in you, give it to the people you love. Don't be surly at home, then go out in the street and start grinning 'Good morning' at total strangers.

The remark urges an ethics of emotional priority: reserve your best warmth for the people who bear the daily weight of your life. It criticizes the common habit of exporting charm to strangers—performing politeness in public—while withholding patience and kindness at home, where one’s true character is most consistently tested. The “one smile” image frames affection as a limited resource under stress, and the admonition against being “surly at home” highlights how intimacy can breed carelessness. The quote’s force lies in its plainspoken contrast between public performance and private responsibility.