The end of the book

Why is it that while I am reading, I can't wait to get to the end. I want to know what happens and how the characters lives change. But, as I near the end I get a sense of sadness. For the time that I was involved in the book, these characters were my friends and now our friendship is ending. Yeah, I will still think about them from time to time, but my daily interactions with them will no longer exist. I finish a book, set it down and sigh because a chapter of my life has ended and I know I will miss what I was just involved in. A beautifully spun tale of a person's life that someone worked so hard on because they wanted to share it with me. I know not really me, but you get my point. Well as I finished my book, my sadness lingers a little. But, I am sure that later tonight as I pick out my next book, that melancholy feeling will began to diminish and be replaced with the growing excitement of meeting new literary friends!