From charging our iPhones to cooking our dinners, the power grid is centrally important to our modern way of life. Imagine what would happen if you did not have access to electricity (think of a power cut lasting for a week).
No lights, no tv, no playstation, no hot breakfast/lunch/dinner, no hot showers, no fridges, no traffic lights, no radio, no internet, no charging phones/laptops/tablets, no computers, no electrical medical equipment in hospitals, no electric trains, no online banking, no... well no anything really. It would be a bit like taking a step back into medieval times.
That's how important the electrical grid is to us today. Remember that next time you switch on a light bulb or charge up your phone and remember to always be as efficient with energy use as possible.