What makes it even sadder is that it's a true story. I actually cried watching this, especially when Hachiko was dying. That was so sad! That last part where Hachi dreams of Parker coming back was so heartbreaking!
What intensified the effect was the marvellous music. It was so emotional and tragic; best music ever! Seriously though, the guy who did it is a genius! Here's it:
If you haven't watched the movie yet, you should.
Hachiko is the most loyal dog ever!