Of all the constructs created to explain the human experience, none has been so reliable as the concept of evil. Throughout time a simple resolution to all that ails a human being morally and ethically has been blaming the situation on evil.
Good, on the other hand, has been transmutable because it is wholly subjective. In one culture stoning to death for a societal crime is simply upholding the just or good of that culture. Western perspectives view that act as anything other than good.
Evil, although constant in function, has taken several different forms, though. Whether one wishes to blame a snake, a devil, a Kali, Hades, vampire, werewolf, ghost, or any number of historical figures that have failed in their machinations, there will always be something to tag with the affiliation of evil to suit the purposes of the moral shortcut.
The concept of evil is something of a copout because it prohibits a logical confrontation of a situation in order to fix the problem.