Is there any particular reason that your favorite song is your favorite song?

For me it was something that happened a couple of months ago. When I learned that the girl I loved would be moving to South Carolina I spent a lot of time moping around. At night I would usually end up listening to some of my dad's CDs. While listening to the song "Summer of '69" I had a sudden rush of memories of this girl only these memories didn't bring me saddness they actually brought me joy. So now whenever I start missing this girl I listen to "Summer of '69"