How productive is it to listen to productivity gurus?

I was making my way slowly through one of my dismally prosaic little to-do lists – ‘pay the water bill’ ‘wash hair’, etc. – when the voice of the journalist Helen Lewis came on Radio 4 talking about productivity. It’s the Holy Grail of modern life, apparently, and we are now constantly looking for ‘charismatic individuals’ to help us maximise it.