1. A robot may not injure a human being or, through inaction, allow a human being to come to harm.
Literally all of them (from what I remember; it's been awhile since I've read the collection) revolve around problems caused specifically by trying to circumvent or modify the Three Laws, the moral of the stories being "This is why the Three Laws in their specific ordering are necessary for robotics to not bring about the demise of humanity".
(As all Asimov's Robot stories pointed out)