Showers (especially hot ones) are one of humankind's greatest inventions. Imagine having to face the day without one. Actually, don't. The idea is too horrible to contemplate.
Tracking down the inventor of the shower proved to be a challenge. Thankfully, inventions.org gave us the scoop. The site explains that the first "rudimentary showers" were found in India, Egypt, and Mesopotamia. In these showers, people washed by either pouring buckets of water over themselves or having servants do it for them. Effective, but lacking a certain je ne sais quoi.
The first real shower (complete with plumbing) was invented by the Greeks. Inventions.org writes that "after exerting themselves in the stadium, ancient Greek athletes would freshen up in the kind of shower depicted on an Athenian vase of the fourth century B.C." The vase in question features four women showering under piped-in water. As the site notes, "the whole scene is amazingly contemporary."
So, there you have it. The Greeks not only invented democracy, philosophy, and the Olympics, they gave us showers, too. God bless 'em.