I would argue that actually modern pluming & water purification is probably one of the most important inventions we have ever seen. Without proper water purification & sewage there would be a lot of sick people in the world from drinking unsafe drinking water. Due to sewage infrastructure we have, our waste could go to a refinement to be cleaned & reused. This is actually probably one of the greatest inventions ever created. & it's all something we look past & take for granted. But in some parts of the world they don't have this luxury we do & the quality of life for them is absurdly bad it's hard to imagine.