evil

an evil plot to brainwash and even kill innocent people

If something is evil, it is never mandatory.

An Odoriferous Specifick […] is a Matter that takes away Diseases from the Sick, no otherwise then as Civet drives away the stinck of Ordure by its Odour; for you are to observe, That the Specifick doth permix it self with this evil Odour of the Dung; and the stink of the Dung cannot hurt, no[r] abide there […]

The owl shrieked at thy birth,—an evil sign;

an evil beast; an evil plant; an evil crop

Global variables are evil; storing processing context in object member variables allows those objects to be reused in a much more flexible way.