Acupuncture stimulates the release of norepinephrine, acetylcholine and several other types of opioids, affecting changes in their turnover rate, normalizing the autonomic nervous system (involuntary), and reducing pain.

Explanation - these are feel good substances!! Stimulation & increase/balancing of them is something we all want!! Pain reduction, reduced anxiety/irritability & elevated mood!!
Acupuncture brings it!!!!!!