Rapport is determined less by what we say, than how we say it. A famous study in the 1960s suggested that, out of our conscious awareness, we take more emotional meaning from people's voice tone and volume, facial expression and posture than from the words they say.

When we adopt similar voice quality, breathing, posture, and gestures as the person we are with, out of conscious awareness they notice and like the similarity, leading to better rapport. Even in situations of disagreement, this can help us disagree without it being disagreeable!

There is more about improving rapport in 'Practical Wellbeing' section 3, and in 'NLP Foundation Course', section 1.