The blue ocean color you see is due to reflections from the sky. Due to the chemical properties of water, pure water with nothing dissolved in it is rarely found in nature. Rivers often look brown or green due to the sand or mud in them. Water is a scarce and precious resource. Unfortunately for us, most of this is salt water in the oceans and seas and much of the rest is frozen on mountains and polar ice caps.
Water is the most important and probably the most widely known substance on the Earth.
But unless there are droughts or floods, most of us don't think about it much. Without water we would not live. It makes up two-thirds of our bodies. All sorts of recreation. Water cools our bodies, carries nutrients through it, lubricates it and carries off wastes.