Politeness is the art of choosing among your thoughts.

Manners are less about what you say than about what you leave unsaid. You have more thoughts in any conversation than are worth airing, and most rudeness is simply the failure to sort them. Not every true thing is equally worth saying, and choosing among them is a skill. The rude person is often just the one who has stopped choosing.

In your next difficult conversation, let one sharp observation go by unspoken and see what the room does with the space. Notice too what you keep back out of care and what you keep back out of fear, because only one of those is politeness.