Devil in Disguise

How do you identify a devil when you see one?
Are they hopelessly ugly or do they wear certain brand of clothes. Do they hate certain things and like the rest? Do they say you are pretty or do they not know know to smile at all. Or are their smiles too deceiving afterall?
Why is it so difficult to draw the line between just another person in a bad situation or a bad person showing their true self in that situation.
Why cant this get easy.