Here is my secret. It is very simple: It is only with the heart that one can see rightly; what is essential is invisible to the eye.
– Antoine de Saint-Exupéry
A famous if controversial study from American psychologist Albert Mehrabian, published in 1967, concluded on the supremacy of non-verbal communication cues over verbal and vocal ones. 
According to him, spoken words, voice tone and facial expressions respectively contribute 7%, 38% and 55% to the understanding of someone’s communication. Put differently, words alone often lack the substance and the subtlety that enable the understanding of a spoken message.
This is why most of us needing to seriously engage another person, ...