Well nature helps bad parenting into ingraining a kids the bad role model's ways. Shithead Ko's are more than willing to imitate their shithead parents, can't say the same if the parent was nicehead, since the shithead kid probably wouldn't listen, same way how a nicehead kid would feel troubled by it's shithead parent's ways. As we know, Yu's are more nature than nurture, So a bad nature will override any good attemp of nurturing, Meanwhile a Good Nature will assimilate any good attemp of nurturing.