Smiley face. Sad face. Smoochy face. Sick face. Edvard Munch ‘Scream’ face. How are you feeling today? Any of the above?

When I worked as a teacher at a Saturday school for children who were struggling with English and maths, my pupils, all of whom were primary school age, had two emotions: they were ‘good’ (breaktime) or they were ‘sad’ (seven times table, spelling test).