A quote from Jo Boaler, inspired by Keith Devlin:

” Mathematics is a performance, a living act, a way of interpreting the world.  Imagine music lessons is which students worked through hundreds of hours of sheet music, adjusting the notes on the page, receiving checks and crosses from the teachers, but never playing the music.  Students would not continue with the subject because the would never experiences what music is.  Yet this is the situation that continues, seemingly unabated, in mathematics classes.

An analogy I have used when trying to explain this to parents, board members etc.:  A certain popular curriculum teaches math as a series of unconnected skills.  Imagine a volleyball team that continually practiced how to bump, to set and  to spike, but never combined the skills and had never played a game.  How do you think they would fare when playing a team who had learned the skills in the context of playing an actual game of volleyball?