We all recognise the stereotype of the fusty, scruffy, highly eccentric, frequently male teacher of mathematics, the person who is deeply unfashionable, has dubious standards of personal hygiene, and has few friends. I am such a person, a female version, and I have spent much of my working life trying to avoid this unpleasant labelling. If being a mathematics teacher means living with a stereotype of social unacceptability, what on earth makes us want to do it?