Ever wonder why people who disagree with us are only infrequently persuaded by the presentation of our case despite the obvious (to us) superiority of our arguments? Maybe it has something to do with our demeanor. Here's the 17th century genius and polymath Blaise Pascal on that very topic. "[All] men in the world," he wrote, "are almost always led to believe not by proof but by agreeableness."
Pascal wrote that there are two doors to the soul, the mind and the heart, but that few enter solely through the door of the mind. He writes that, "[People] are introduced [to belief] in large numbers through the whims of the will, without the counsel of reasoning." In other words, most of our beliefs are based upon our desires, biases, prejudices, etc. We believe that which appeals to our subjective feelings, not our objective reason.
He adds that, "...whatever the point about which one wants to convince someone else, one must be attentive to that person: one must know his mind and heart, what principles he accepts, what things he loves....So that the art of persuasion consists as much in pleasing as in convincing, given the extent to which men are governed more by caprice than by reason!"
"The heart," he's famous for having said, "has reasons which reason can never know."
The door to the mind lies behind the door to the heart. If the latter is closed the former is often inaccessible.
Thus, if our mode of disagreement is angry, humorless, arrogant, and insulting we can be sure we'll gain few converts to our views. Such behavior closes the door of the heart. On the other hand, humor, kindness, and humility often cast wide the door to a person's heart. They often gain us a hearing even among those otherwise undisposed to listen to us, but once the door to the heart has been open, the door to the mind is also more likely to be set ajar.
At that point we need to be well-supplied with facts and able to deftly employ reason if we hope to pry open that door even wider.