Dangerously clean

‎In fact, super-clean water tastes flat, heavy, and bitter. The opposite of what we like. The appealing freshness in water comes not just from it’s temperature and its appearance, but from a sprinkling of salts and minerals that give it a crisp taste.
-- The Dangerously Clean Water Used To Make Your iPhone

So our bodies are tuned to enjoy water that is just the right amount of cleanliness. Not too dirty and not too clean. Fascinating.