I always wait for the shorts to help me buy at a bargain and I have a feeling I'm not the only one.
The shorts have conditioned me not to get excited when its going up and try to buy before the cheap prices are gone forever because, no matter what (however briefly) the cheap prices will come back.
Rather I will wait after a spike for the shorts to beat NWBO up and then buy, maybe using limit orders.
When you multiply my behavior by hundreds or thousands of other investors that is going to seriously retard the share price.
As institutions participate more and more (or if we got publicity and pulled in some new, non-jaded retail investors) then this factor will diminish.
But for right now, the shorts have burned retail investors so many times that I think this is why few of us really feed the rallies (which makes what has happened in the last few weeks all the more remarkable).