Why do we dislike the sound of our own voices?

On Ask! the Naked Scientist this week: What led to the 'leopard spots' found on Mars? What is the purpose of finger and toe nails? How do bone conduction headphones work? Why do non-magnetic metals sometimes interact with magnetic objects? What role did our teeth play in our evolution? What’s the cause of my unintended weight loss? Could astronauts create an environment for life on Mars? What’s wrong with a pear shape?