Evil for the sake of evil can only get you so far, it's fun, it's mindless, and it'll serves its purpose if you know what you are doing.
But in the end, a villain is like the protagonist, they have a background and past that shapes them to what they are now, to why they do what they do. It's just that a villain, concluded something in the wrong way for either the eyes of society, an individual, or even us!
Remember, villainy and heroism are a matter of perspective.
NOW CAN YOU FUCKIN STOP SKEWERING MY PERSPECTIVE MORIARTY, GOD!!!!! AND I KNOW, I FUCKIN KNOW WE ARE COMMTING GENOCIDE, LEAVE ME THE FUCK ALONE!!!!!!!