Sara Bareilles - Bottle It Up

I really would like to keep writing a post everyday or at least 5 a week
but I have some struggle about what song to write
I mean, analysis does take some time to do right?
and picking a song to write about is not easy as well

anyways, I decided to write Bottle It Up by Sara Bareilles
who just released her newest album
I don't remember when did she release this song
but I know it's released in her album Little Voice with Love Song
I guess it's around 1-2 years ago
Bottle It Up is a really good song and I fell in love at the first time I listened
Nice groove and arrangement
Let's start from the instrumentation
It starts with just vocal, Bass and drums
with a nice up beat groove
and guitar comes in at the 5th bar
Then 2nd guitar and piano comes it at the end of 1st verse
and All instruments follow with the same groove
(awesome!! I just love that~!!!^^)
BG Vocals come in at chorus
Piano, Bass line and guitars change
then it goes back to verse and all instruments go back to the groove
and repeat chorus
In Bridge, all instruments drop except piano, bass and drums
the groove matches so cool in piano and bass
and guitar enters at the 2nd half of Bridge
Synth and piano only when it enters back to chorus
and outro with all instruments

There's a brief instrumentation
and about the vocals
Lead comes in at the very begining
clear with reverb
in pre-chorus I guess it adds a little more reverb
and the 1st and 2nd BG vocals enter with just harmonies
(though I think it's kinda buried in the guitars)
(PS the 2nd chorus added some adlibs)
however, in bridge the harmonies have taken a very important role
Texture Harmonies, Lyrics Harmonies and descents are all in the bridge
especially the descents is very well written
that just uplifts the whole song at bridge
the Lead voice verb was brought down a bit
and at the end the descents has given the section great ending

in terms of the chords
this song is in C major/A minor
Chord progression is basically
Verse Am/Em/F/C/G
Pre Verse Am/Am(/Ab)/Am(G)/F 
Chorus C/Em/Am/F
Bridge Am/(Ab)/(G)/(Gb)/Dm/(Db)/(C)/(B)

Actually the chords combination make a very interesting contrast
and that makes this song special too

in conclusion, I really do like the song
with all the great arrangement and production
especially the awesome groove
PS-I am thinking maybe this song will be my class project this month
since I figure everything out right?