"Think of Me" from Phantom of the Opera
Its strange when all of a sudden someone from your past comes into your mind; its even more strange when you start thinking of them and then can't get them out of your head. Its like all of these different memories come flooding over you. Its sometimes nice to just sit and let those ideas come washing over you, however, sometimes those can lead to bittersweet thoughts. However, it is my experience that "it is better to have loved and lost, than to have never loved at all."
I like to sing this song when I remember someone and wonder if they remember me at all, too.