How does it do it?

Honestly, how? It only takes once and then bam its in. You don't even have to know it in its entirety. It just happens and won't stop, and the only way to make it stop is to get more of it. What is it? Songs. They have an amazing ability to get stuck in your head. You only have to hear it once and its in there. They have some amazing ability to control our thoughts with a song repeating over and over again. Today I heard a song on the way to work and it stuck in my head for the entire work period. The only way to get it out was to listen to the song enough until I got sick of it. It still amazes me that I listen to a song for three and a half minutes on the way to work and five hours later its still repeating over in my head as if I heard it two minutes ago. I listen to it over and over in my head and ask myself, how does it do it?