Rest is not idleness, and to lie sometimes on the grass under trees on a summer's day, listening to the murmur of the water, or watching the clouds float across the sky, is by no means a waste of time.
We cannot afford idleness, waste or inefficiency.
Idleness is to the human mind like rust to iron.
I don't think necessity is the mother of invention. Invention, in my opinion, arises directly from idleness, possibly also from laziness - to save oneself trouble.
Idleness is the stupidity of the body, and stupidity is the idleness of the mind.