Acts of kindness can mean the world to someone else, especially someone who is in crisis. When asked, "What is the most selfless thing someone is unaware they did for you?" people shared stories on Reddit of events, small and large, that sometimes dated back decades. One person said a social worker who had rescued her from human trafficking wrote to her about the importance of their encounter. "The day I got the letter I was prepared to kill myself," she wrote. "She saved my life and has no idea."