The bad guys (and gals, if 'guy' isn't a gender-neutral word to you. You're not limited to only binary-gendered species though, nor to beings that even have a gender.) of science fiction. You love them, or hate them, or love to hate them.

My nominations are Darth Vader, from Star Wars, Jean-Baptiste Emmanuel Zorg, from The Fifth Element and Lady 3Jane Marie-France Tessier-Ashpool, from Neuromancer.

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If we don't play god, who will?-James Watson
I never think of the future, it comes soon enough.-Albert Einstein
The large print giveth and the small print taketh away.-Tom Waits
Any sufficiently advanced technology is indistinguishable from a yo-yo.-Enoch Root, The Confusion
When I was a kid, if someone brandished a shrink gun he'd get a little bit of respect!-Myron Reducto, Harvey Birdman