I don't know if these are the right chords, I was playing the song on my guitar 
and it sounded alright (:

Capo 8

C         Am        F              C
I shoulda known when I got you alone
C         Am        F               C
That you were way too into me to know
C         Am        F               C
This isn't love boy, this ain't even close
C         Am                G                    C
But you always think we're something that we're not


C          Am         F               C
And now you call me every single night
C          Am   F                C
I only answer cause I'm too polite
C           Am        F              C
We happened once, or maybe it was twice
C           Am          G                C
Yeah you always make it hard for me to stop
C           Am             G                    C
But you always think we're something that we're not


C            Am   
You wanna be more than just friends
F               C
I can't go through this again
C               Am    F    C
Stop trying get inside my head
C               Am
Don't wanna do more than hookup
F            C        C                Am    G      C
It's getting stupid, cause I shoulda known but I forgot
C        Am          G                    C
That you think we're something that we're not, hey! 


Same for the rest of the song (:

I hear you're telling every one you know
That I'm the one like you can't let me go
And you just keep on blowing up my phone
Cause you never seem to know when you should stop
Don't introduce me to any of your friends
Delete my number, don't call me again
We had some fun, but now it's gonna end
But you always made it hard for me to stop
Now you always think we're something that we're not, hey! 

You wanna be more than just friends
I can't go through this again
Stop trying get inside my head
Don't wanna do more than hookup
It's getting stupid, cause I shoulda known but I forgot
That you think we're something that we're not, hey! 

Something that we're not, hey! 
You think we're something that we're no
Yeah, you think we're something that we're not

Not gonna happen, dude.

You wanna be more than just friends
Don't wanna go through this again
Stop trying get inside my head
Don't wanna do more than hookup
It's getting stupid, cause I shoulda known but I forgot
That you think we're something that we're not, hey! 

You think we're something that we're not
Something that we're not
Stop playing
You think we're something that we're not
But you think we're something that we're not