Make Them Think They're Right

    Nobody believes that they're wrong about something they believe in--it's contradicting. A dog who chases cats doesn't think its evil to do so, nor does a cat believe that his/her playing with and eating birds is cruel and merciless (unless of course animals are all secretly evil maniacs. I doubt it).
    Likewise, I think a majority of villains/antagonists in fiction are like that. They don't think they're evil. In their minds, their actions are justified, they're doing what's best. The protagonist is the one doing evil things, and that they must be stopped.
    In essence, antagonists think that they're right, that they're the good guys.
    What's your antagonist's reasoning for their actions? Do they think they're right, or do they know they're being immoral but want to use that to their advantage?