For a few moments you ARE the person you were in your memory. For a few moments. THAT'S why nostalgia is so bitter sweet.

NOSTALGIA IS DISSONANCE BETWEEN THE VIVID RECOLLECTION OF A DISTANT, USUALLY PLEASANT MEMORY, AND AWARENESS OF JUST HOW MUCH TIME HAS ELAPSED SINCE THE EXPERIENCE BEING REMEMBERED; THE MIND STRUGGLES TO RECONCILE WHO YOU WERE THEN WITH WHO YOU ARE NOW