To me, it feels like the singer is visiting somewhere that is tightly bound to some portion of his life; his hometown or college, for example. Walking the old streets, seeing the old sights has conjured up the memory of the person he was when he lived there. He is singing this song to the ghost of his former self, but he isn't mourning the loss of better days; he is playful, almost teasing.
To me, it feels like the singer is visiting somewhere that is tightly bound to some portion of his life; his hometown or college, for example. Walking the old streets, seeing the old sights has conjured up the memory of the person he was when he lived there. He is singing this song to the ghost of his former self, but he isn't mourning the loss of better days; he is playful, almost teasing.