Capo I or IV (they actually play it on Iv but I find it easier to sing with the capo on 
the first fret)

(single strumming)
          G
Should've kissed you there
            D
I should've held your face
            Em
I should've watched those eyes
           C
Instead of run in place
            G
I should've called you out
            D
I should've said your name
            Em
I should've turned around
            C
I should've looked again

 Chorus :
    D   Em                 C      G      G
But oh, I'm staring at the mess I made
Em                  C      G
I 'm staring at the mess I made
Em                  C      G
I 'm staring at the mess I made
       D         Em                  C       G
As you turn, you take your heart and walk away


(strumming)
          G
Should've held my ground
           D
I could've been redeemed
          Em
For every second chance
                C
That changed its mind on me
            G
I should've spoken up
            D
I should've proudly claimed
           Em
That oh my head's to blame
         C
For all my heart's mistakes

 Chorus :

    D   Em                 C      G      G
But oh, I'm staring at the mess I made
Em                  C      G
I 'm staring at the mess I made
Em                  C      G
I 'm staring at the mess I made
       D         Em                  C       G
As you turn, you take your heart and walk away

    G     D       Em    C
And it's you, and it's you
    G     D       Em    C
And it's you, and it's you
         G       D            Em    C
And it's falling down, as you walk away
         G      D          Em  D
And it's on me now, as you go

 Chorus :
    D   Em                 C      G      G
But oh, I'm staring at the mess I made
Em                  C      G
I 'm staring at the mess I made
Em                  C      G
I 'm staring at the mess I made
       D         Em                  C       G
As you turn, you take your heart and walk away


         G       D            Em    C
And it's falling down, as you walk away
         G      D          Em  D
And it's on me now, as you go


 Chorus :
    D   Em                 C      G      G
But oh, I'm staring at the mess I made
Em                  C      G
I 'm staring at the mess I made
Em                  C      G
I 'm staring at the mess I made
       D         Em                  C
As you turn, you take your heart and walk away