the connection between two sentences

[Saneta]

Please tell me the connection between these two centences from my grammar book (I can't see it) :
''I couldn't agree with you more. You are quite right (=You are completely right)''
I would say instead of the first sentence:
,, I couldn't disagree with you more. You are quite right'' or ,,I couldn't argue with you more. You are quite right.''
Thanks!

[Kitosdad]

''I couldn't agree with you more," confers on the other speaker absolute agreement with what has been said.
_________________
Keep it simple ... Keep it interesting.

[Saneta]

,, I couldn't agree with you more''=,, It is enough with what I can agree with you.''?
I think at last I caught on this. Thank you Mr Kitos, people can e-mail you, but what is your e-mail address?

[Kitosdad]

Thank you Mr Kitos, people can e-mail you, but what is your e-mail address?

Kitosdad at googlemail.com
_________________
Keep it simple ... Keep it interesting.

[Saneta]

Sorry, but I don't understand,what is your address? kitosdad@googlemail.com????????