So what is better: Fire, the wheel, or indoor plumbing?
I think indoor plumbing is the shit; Fire and the wheel are both naturally occuring (in that nature supplies fire and cylindrical-ish objects, like tree cross-sections). Indoor plumbing, however, is something we humans created. We took the element that covers 2/3 of the Earths surface (in surface area only! not even counting pure volume) and managed to force it to do our bidding. We're able to pump millions of gallons of water to millions of houses and then decide to turn it off if we want. We can fill a 40,000 gallon pool at the twist of a knob and a little patience; we can take a shit and have it magically be taken away to a much better place than anywhere near my house.
Discuss.