Too many faces in schools are "pursed up like a dog's bottom", according to Jenny Mosley, founder of the massively successful circle time initiative.
Children suss out weaknesses in staff, play one teacher off against another and "smell insincerity". But teachers must always try to show empathy, warmth and genuineness. "The one who most needs me is the one who most repels me," Ms Mosley said.
Addressing the annual conference of Roman Catholic primary heads in Dunblane, Ms Mosley said staff self-esteem was just as important as the focus on circle time, which aims to raise the self-esteem of pupils and improve the ethos of the school.
"If I was a headteacher I would bring in a facilitator once a month just to have a staff meeting on the psychology of children, on feelings and on how much energy we have, because we need to speak about our feelings. We need to understand our own behaviour and the behaviour of children who wind you up," she said.
Too often teachers dominate the conversation after gathering children round. "There is too much control, too much voice of the teacher, too much sitting and not enough movement. It should be very exciting but it's not," she said.
Children grasped that circle time, done well, was about good citizenship but they could see adults outside circle time who did not show enough respect to each other. "You can have all the PSHE (personal, social and health education) stuff on the wall but it lives in the heart and how people relate to each other, how adults demonstrate they can cope with conflict and tension, how they settle differences between people. It's hard work and it's hard not to show things in your face," Ms Mosley said.
The starting point was staff relationships. If they had challenging children, did they get together in twilight sessions to discuss such behaviour and their own reactions? If their response was "very tense and tight", children would respond to that.
"What worries me is that there is too much moaning going on. It is a dreadful ethos because it saps energy and goes into your system. It's called psychoneuro-immunology. It affects the mind and the body. The more you moan and get into a flam the more difficult it is to get up in the morning, the more you get illnesses and you go down."
Ms Mosley added: "But it's not worth moaning. The message is either that you make your job work or you leave. What a child needs is for you to be a superhero. What the child needs is for you to pick yourself up off your knees every day and come in and be positive and look for the good in that child. It's to do with generosity of spirit. That's why teaching is a profession and a superhero job."
Headteachers had to encourage staff to have fun in school and to have a life outside the classroom. "The best schools are emotionally safe where it's all right to make a mistake and ask for help and not be judged. If you feel safe enough with people, you'll try something new," she said.