So, what's acupuncture good for?

The World Health Organization (WHO) has put together a list of things that acupuncture has been shown to treat, but it's probably more illustrative to consider this: 

Acupuncture has been the defining mode of treatment for the core system of healthcare in East Asia for more than 2200 years, treating any and every disease that arose in those cultures.

Acupuncture was developed, not as an isolated technique to treat a specific disease or set of illnesses, but as  a dynamic system to help the body deal with all the injuries and insults that life throws at us.