What it does to them

The reading is silent, and it feels as though it costs no one but you. It doesn't.

Living with someone who takes moods personally means learning to manage your moods around them. Not to be tired at dinner, because tiredness will be read. Not to send a short reply, because short will be read. To perform a warmth you don't have at the end of a bad day, because the alternative is a second conversation about why you're quiet, and you haven't got one in you. Over time the person you live with becomes, near you, less tired than they are, less short than they are, less themselves than they are, and they carry the bad day somewhere else, or nowhere.

There's the reassurance job. A partner who knows that quiet gets read learns to pre-empt it. "Bad day, nothing to do with you." It's a kind thing to say and after a few years it's a tax, paid at the door every evening, and the person paying it has started to feel that their bad days are yours to be managed.

There's what a child learns. A child who watches a parent take every mood personally learns that moods are aimed, and grows up reading the world that way, and the reading is inherited the way most habits are, by being watched at a kitchen table.

There's the friend who learns to reply fast, not because they want to but because a slow reply produces a cool week, and the friendship becomes a thing to be maintained rather than enjoyed.

And there's what the reading does to their bad day. A person who comes home with a rough afternoon and finds that the rough afternoon has been read as an attack now has two things to deal with. The afternoon, and you. The one place they could have put the day down has become the place where the day gets turned into a question about them, and they'll stop putting it down there.

None of this is what you intend. You intend to notice and to care. But the reading, unchecked, arrives on the other side as surveillance, and people who feel watched behave like people who feel watched, which is carefully, and carefully isn't close.