This has always been one of my favorite holiday songs. It really isn't a Christmas song, but they always seem to play it this time of year. There is just something about being able to look back on the past with fondness. It is something that can be recaptured for a little bit of time, but it is not something that can be retained. It is the past. Our memories are really waht should be cherished.
Enjoy the past and look back!