I've heard that if you practice the correct vices hard enough they'll cancel each other out.
At least one poster mentioned the fact that the scope magnifies the "shaking". I agree. I find myself overcompensating my natural sway (which I think we all have to some degree) with a scope. If I use open sights I can't see my POA changing as finely and therefore I adjust less. I can shoot offhand with open sights much better than with a scope. When I am going for my tightest groups with a scope, I sit and rest the gun on a bag. If I want clean "humane" shots on pests, squirrels, ect.... I side rest on a tree or whatever I can. But, most of my shooting is target and I use the bag. I have a couple tripods but I don't get the opportunity to use them often because I seldom shoot anywhere but at home.