Should we be concerned that the sun will burn out before the moon is up? Can we save daylight time by keeping garden or entrance lights on? Were you ever late to a meeting because you flicked a light switch on your way there? If you step in elephant dung, does it matter if it was excreted on top of bird droppings? If the luminescence of direct sunshine is a thousand times that of a compact fluorescent light bulb, do we need the light when the sun is on? Have you ever used neon lights to keep warm when standing outside? Unless you have answered ‘yes’ to any of these questions, can you please turn off the light when you leave the house on a bright sunny day.