I Couldn't Agree With You More
Meaning/Usage: To completely agree with someone
Explanation: This is the highest level of agreeing with someone because they can't agree more than they do. It is straightforward and very common.
I couldn't agree with you more, this place is beautiful.
I couldn't agree with you more, spending more time with each other would be nice.
You didn't like that movie either? I couldn't agree with you more.
A.
I really don't like shopping around the holidays.
B.
I couldn't agree with you more. It's always so busy.
Other Common Sentences
I totally agree with you.