I totally agree with you!

Well actually, I don't agree! The title phrase is one of my pet hates. I hear my students say it in interactions and frankly, my heart sinks with boredom.                                                                                         

What's wrong with it? Nothing at all; it just doesn't take the dialogue anywhere interesting. Your opportunity of showing the examiners that you speak fantastic English is very brief, and the topics are not necessarily very interesting, so agreeing so totally is a waste of time; all it does is show that you are familiar with a set expression.

So what should you do? How about: "well I agree with you up to a point, but don't you think..." "yes, but what about...""that's a thought. Here's another idea:..."

Spice it up a bit. Disagree (politely) This gives a lovely opportunity of showing your use of stress and intonation. "I don't think so. I think grammar should be demonstrated  rather than being explained "