Why do we care so much about the hair on our heads? Each year we spend billions of dollars on cutting, shaping and colouring our hair. It's important for personal reasons, cultural and symbolic reasons too. But why? Find out, as we hear the stories of people who have had their hair taken from them. Join Mike Williams for The Why Factor.(Image: A US soldier getting his head shaved. Credit: JOHANNES EISELE/AFP/Getty Images)