Our social intuition is strong. Here is one of my favorite quotes on this topic, by Sigmund Freud:
Psychological discernment is not as difficult as one might think: Those who have eyes to see and ears to hear soon become convinced that mortals cannot keep a secret. He whose lips are sealed talks with his fingertips; disclosure oozes out of his every pore.
“Fragment of an Analysis of Hysteria” (1901-5), VI, 148
This speaks to two things. The first is that when two people are arguing, rather than engaging in reasoned discourse, both spend more time thinking of their next clever riposte than listening to what the other is saying. The second is the human inability to prevent ourselves from communicating our thoughts through microbehaviors.