Also they pick extremely specific spots in acupuncture. They also don't go very deep. The point of acupuncture is to hit specific points that will release relaxing chemicals and it's not meant to cause any pain at all. Where as sticking one's self with a needle is not quite so methodical, you could hit a vein or nerve and not realize that one was there.

I believe that is the difference. However I agree very mych with Sannah as well.