Each human being has a very unique patchwork of genetic beginnings plus life experiences which eventually mold into quite personal definitions regarding every conceivable topic ... what is good, what is bad, what is ethical, when to be skeptical (and when not), ad finitum. My own concept of "being skeptical" means that in response to some stimulus, my mind is automatically flooded with questions ... What? Who? Why? When? Where? Each "answer" to any of these questions then raises new questions. 

To be honestly skeptical, there is one more extremely important question: "What is MISSING in my own perceptions and interpretations?" This last question delves into the "blind spots" in  any person's responses to external and internal events. This is critical. 

The Biblical admonition to "beware of false prophets" is a statement to be closely examined for the who, why, when issues ... and also the "blind spot". Religious/supernatural acceptance raises questions of what one does not see.