Water is life. Treat water with respect and gratitude. In other words, do not waste water unnecessarily. Obviously, some countries are more fortunate with the availability and price of water than others, but that does not mean you have to waste it.
In the wonderful book The Hidden Messages in Water you can learn more about why you should respect water.
For those who understand French, the song "8 Secondes" by the Canadian group "Les Cowboys Fringants" says a lot about the mismanagement of the Earth's water resources: