It’s never really that people don’t understand; we always say it as if they are somehow confused, when they are not. Like this:
• Why do people fail to understand that if someone should expect to be criticized every time they walk into the room, to the point that one can actually watch people look around for something to complain about, then no, that person will not want to be in the room with you.
It is not that everyday belligerence doesn’t understand; these people do. It is not that they are somehow confused about why the constant hostility distresses anyone; they aren’t.
If there is any one thing you ask people to not do, they will do it.