I connected two ends of battery with copper wire, and nothing happened. Why?
1.5v isn't enough to "electrocute" you. In fact, it may not even be enough to make a visible spark when you short the battery. (Shorting a battery is, by the way, a Bad Idea. There's a chance of leakage, overheating, all the bad stuff.)

If the battery and the wire didn't get warm during the short, the battery probably wasn't any good to begin with. Even a AA should change noticeably. Maybe there's something wrong with your motor construction? Weak magnets? There are a lot of improvised motor designs. Post a link to the one you're using and maybe some hypotheses can be raised.