She may have been your first girlfriend, or she may have been a girl you met a few months ago. You've thought of her from time to time, but life is busy, and you've decided to move on with that, and get busy with it. Occasionally, it bothers you that you think of her at the most inopportune times, or have a dream about her. You'd thought you managed to forget, or come to the very logical conclusion that it's not convenient or healthy to harbor any more thoughts of her. But still, she won't let you go. Or maybe it's only the memory of her that won't.