Kermit the Frog, of enduring Muppets and Sesame Street fame, was always a favourite with my children and me: he was so amusing and appealing, and also had a way of unobtrusively communicating simple goodness along with the occasional moral message. He was also concerned with the most important matter of the self, so that in his most famous song he puts a positive spin on the matter of greenness, the colour of envy and jealousy. By Gillian Bouras