Last week, on a fine sunny day, I saw a woman teaching her grandson to ride a bike in the park. I say ‘teaching’ but in fact neither teaching nor learning were in evidence. She gave him no advice of any use other than ‘put your feet on the peddles and go’. She was patient and encouraging. Her love for the little boy was obvious to all who had eyes to see. But as a teacher of the fine art of bike riding, she was bloody dreadful. After quite some time, the little boy got off the bike rather angrily and said “you do it then!” There was a momentary…