You can play C instead of C6 to make it easier however this results in it sounding "happier" than the
original.
Partly this is because reverb and bass used by Jamie convey a melancholic feeling in themselves
but also because at some part you hear a line of single notes alternating between an a and an g.
Therefore the Chord would actually jump between C and C6. Same goes for F and Fmaj7 and Am and Asus2.
Video source: https://www.youtube.com/watch?v=S-C-pOR6QP4
[Intro] x6
F C6 Am G
(With you) (With you)
[Chorus]
F C6 Am G
On a seesaw Up and down
F C6 Am G
On a seesaw Up and down Up and down with you
F C6 Am G
On a seesaw Up and down
F C6 Am G
On a seesaw Up and down Up and down with you
[Verse 1]
F C6 Am G
I see pictures in my mind
(With you) (With you)
F C6 Am G
I see fingers up my spine
(With you) (With you)
F C6 Am G
I saw my heart break in two
(With you) (With you)
F C6 Am G
I saw her again with you
(With you) (With you)
[Chorus]
F C6 Am G
On a seesaw Up and down
F C6 Am G
On a seesaw Up and down Up and down with you
[Same as intro] x6
F C6 Am G
(With you) (With you)
[Verse 2]
F C6 Am G
I can see it your eyes
(With you) (With you)
F C6 Am G
I see through your thin disguise
(With you) (With you)
F C6 Am G
She was always my best friend
(With you) (With you)
F C6 Am G
I saw you with her again
F C6 Am G
I see pictures in my mind
F C6 Am G
I see fingers up my spine
F C6 Am G
I saw my heart break in two
F C6 Am G
I saw her again with you
(With you)
[Outro]
F C6 Am G
(With you) (With you)
F C6 Am G
F C6 Am G
F C6 Am G
[Voices]
N.C.
Just stuff..
N.C.
I just..
N.C.
The world just..
N.C.
I just..