(CNN) For the past year, Laura Miller has been living a double life of sorts: administrative assistant by day, secret agent of kindness by night. The 32-year-old Duquesne University employee only recently revealed herself as the woman behind "Secret Agent L," a giver of random acts of kindness that has been brightening the days of unsuspecting Pittsburgh, Pennsylvania, residents since July 2009. The project began, Miller says, with the birthday of one of her blog readers who had become a close friend. But instead of asking for the latest book on the best-seller list or an iTunes gift card, the friend suggested Miller perform an act of kindness in her name. So with a single, lavender hydrangea bloom tucked under the windshield wipers of a random vehicle, Secret Agent L was born.