Mariah Carey - All I Want For Christmas Is You

To celebrate the Christmas season, I thought it would be appropriate to work on a Christmas classic. I ran across an article by CBC news which relays news about the Associated Press reporting that Wham!'s Last Christmas was voted the most-hated holiday song in Bulgaria.

In my opinion, another song that is equally annoying is Mariah Carey's All I Want for Christmas Is You. 

Instead of purchasing sheet music for this song, I decided to dictate the chords by ear.
Since there were a couple of incomplete chords in the recording, I placed a chord that I thought  fit the harmonic structure of the music. For example, the A7add9 chord in the bridge is actually 
missing a C# (I could be wrong...but I can't hear it!). I placed brackets around these incomplete chords.

Please note that the lyrics below is improperly formatted. I didn't break up verses in order to save some space.

Sources

YouTube Video:  Mariah Carey - All I Want For Christmas Is You

I reformatted/edited lyrics borrowed from ultimate-guitar.com and added my own chords.

Analysis

<SLOW INTRODUCTION>

<FIRST VERSE>
G
I don't want a lot for Christmas there is just one thing I need
C                                            Cm
(I) don't care about the presents underneath the Christmas tree
G
I don't need to hang my stocking there upon the fireplace
C                                                 Cm
Santa Claus won't make me happy with a toy on Christmas day
G                              B7   Em                                Cm6/Eb
I just want you for my own, more than you could ever know
G/D                         Em    C                 D7               G
Make my wish come true...All I want for Christmas is you, you, baby

<SECOND VERSE> (...Same chord progressions and placement as first verse)

<BRIDGE>
B7                                Em
All the lights are shining so brightly everywhere
B7                                 Em
And the sound of children laughter fills the air
Cm                              G                Em
And everyone is singing I hear those sleigh bells swinging
(A7add9)
Santa won't you bring me the one I really need
(G/D)
Won't you please bring my baby to me

<THIRD VERSE> (...Same chord progressions and placement as first verse)

<CODA>

This song is harmonically interesting because it contains uses of modal mixture, secondary dominants, and the augmented "French Sixth" chord.

Modal mixture is the practice of borrowing chords from different keys that are related to the tonic. In this song, the C minor chord is "borrowed" from G minor, which is the parallel minor key of G major. This is easy to find because the pitch Eb is not in the G major scale. 

A secondary dominant used in this song is B7. B7 is the V7 of Em. In Roman numeral analysis, the B7 can be labeled as "V7 of vi". The A7add9 is also a secondary dominant chord. It's the V7 of D major and can be labeled as "V7 of V". 

The French Sixth chord is the Cm6/Eb. A French Sixth contains the scale degrees b6-1-2-#4, which are the pitches Eb-G-A-C#, respectively. The b6 and #4 have strong tendencies to resolve down and up to scale degrees 5.