It was always the same sort of system with us. We would write the nucleus of the song, the melody primary music, and then some of the words were there as we finished writing it. I started playing some rock 'n' roll piano and started boogie woogie-ing my left hand, and that inspired Mariah to come up with the melodic [Sings.] 'I don't want a lot for Christmas.' And then we started singing and playing around with this rock 'n' roll boogie song, which immediately came out to be the nucleus of what would end up being 'All I Want For Christmas Is You.' That one went very quickly: It was an easier song to write than some of the other ones. It was very formulaic, not a lot of chord changes. I tried to make it a little more unique, putting in some special chords that you really don't hear a lot of, which made it unique and special.