There were only two such moments:
An online friend (actually the only one I ever made), who lives on the other side of the world sent this brief message: "Welcome Home", the very moment I returned from a college trip. It's nothing uniquely special but I guess it was the precise timing or the unexpected warmth of a simple message. It was a very memorable feeling.
Also, my first and only boyfriend said to me on the day he went back to his country, "I'll always love you, my dear soul." That was the nicest thing anyone's ever told me.