Water
We are becoming more and more aware that water is the essential life-giving liquid and that it should become our basic drink. We usually focus only on its quantity as the mantra that an adult person should daily drink between 2 and 2.5L of water is already generally known.
Yet, we do not consider its quality enough. We obviously want to drink pristine water but in doing so we accept everything above the officially set standard to be of the same quality.