What song did the single " Last Christmas " lift it 's melody from ?
" Who you are at that time , what kind of music you like , what kind of beats you 're into , what kind of state of mind you 're in , what you 're attracted to ... it 's all very telling of where you are in your life at that point ... Twenty years from now , if I give this to one of my kids , I 'll be like , ' This was me then , at that moment . ' "