Nostalgia is a sentiment of sentimental yearning for the past. It is a bittersweet emotion that is often associated with memories of happy times, but also with a sense of loss and longing for what has been left behind. NOSTALGIA can be triggered by a variety of things, such as music, smells, or even a place. It is a powerful emotion that can evoke strong feelings of NOSTALGIA and a desire to return to a simpler time.