Coffee!

 So I've been learning a lot about how coffee shaped the scientific and industrial revolutions. The switch from intoxicating booze as the primary source of clean drinking water to coffee was probably one of the more influential causes of both revolutions. Coffee houses were often called "Penny Universities" because they would allow anyone, for the price of a cup of coffee, to learn from the educated individuals within. Coffee changed the fact that the vast majority of city populations of the day spent most of their time at least slightly drunk. You can't have a scientific conversation while intoxicated!

During the construction of the Transcontinental Railway, Asian workers were more valuable to the companies that hired them because, strangely enough, they seemed to be immune to cholera and other water-borne diseases. This is because they boiled their water to drink tea. 

The safe and effective consumption of water was, before the spread of coffee and tea, a tradeoff. You either risked getting typhoid and other diseases, or you drank beer and went around a bit tipsy all day long. The end of this compromise is celebrated as changing the fabric of human society. 

So when you drink that cup of coffee, even though you probably have clean water in your tap, remember that it's probably responsible for many of the things we take for granted today.