Under My Skin

I need someone to explain to me why this song just won't be shaken off my head. Heard it by chance in a commercial and because I have known it all along it has been buzzing in my head for days now! This is a pure case of admiration of the mere song, mind you, the lyrics, the performance, the soft jazz, yet there is no one that I relate this song to. Yeah, that weakness I have is endless when it comes to the blues and soft jazz I know. You just cannot help closing your eyes and delving deep in that world of beauty once that lady starts. It's under my skin I guess.