Many of our vocabulary words are "moon oriented." The words "honeymoon" "'lunatic" "moon madness" and "moonflower" would not exist. And try to imagine us without that showy social past-time of "mooning!"
Earth would spin much faster without its orbiting moon. That's because the moon's gravity pulls on Earth's oceans. The moon is largely responsible for the tides. The pull of the moon, and ebb and flow of the tides, puts the brakes on Earth's daily rotation. Billions of years ago, Earth spun around on its axis much faster. At one time, the cycle of day and night was less than ten hours long. If we'd never had a moon, we'd still have a shorter day.