Who is your favorite villain in any movie, book, or tv show and why? And if you were to make a villain how would you make him or her? Personally, my favorite villain is Thrawn from Star Wars Rebels, since he is able to predict everything that the rebels are going to do and is known to have defeated the Vong in the Unknown regions in the Star Wars Legends series. If I was to make a villian, I would make him not as smart as Thrawn, but not a complete idiot, and have him enough connections to be able to have some eyes within his enemy's ranks.
Grand Admiral Thrawn was the very first name to come across my mind when I saw the topic title. Dood was one of the best villains created in any genre. One of the things I like most about him was that he was never inherently evil like Palpatine, yet not some misguided tool - he knew what he was doing, and he had the knowledge and power to do exactly that. He was relatable because he was someone who worked his way up the ranks, and even when he messed up he found a way to overcome it (except, obviously, when it came to defeating the plot-armoured Skywalkers and co., because God forbid evil defeats them except at the hands of their own, rather than by an outsider; I mean, even in Fire Emblem: Genealogy of the Holy War, Arvis (who is basically the main villain) is related to one of the heroes). Outside of him, some notable villains I've encountered are Nergal (Fire Emblem: Blazing Sword), GLaDOS (Portal), and Saren Arterius (Mass Effect).
I do admire Grand Admiral Thrawn too, but to say he's my favorite...its hard to pick a favorite from all the amazing entries out there. For this thread though, I'll go with someone like Thrawn but completely different, Major Tanya Von Degurechaff. This character is amazing. She is cold, calculated, and ruthless. She sees where the great war is headed when no one else can and tries to do everything she can to get a comfortable position in the rear, but because she continues to demonstrate her usefulness in the battlefield to get that promotion, she continuously gets sent to the front. She uses her wisdom to out predict her enemies, she has strength and power that can not be rivaled, and when she's on the battlefield, she's like a giggling school girl playing with others lives. Whenever I see her on screen with that sadistic smile, I can't help be get excited to see what she has next. Other recommendations, Light Yagami, Hansom Jack, Red Eye, and many more.
Cesare Borgia from Assassin's Creed Brotherhood, purely because his timing is so spectacular that he appears every single time where you are annoyed.
Scar and the hyenas from The Lion King. I just think they're really cool. Vitani from TLK2 is really cool as well, though by the end of the movie she isn't a villain anymore, so I guess she only half counts. Other favourites RBA from Attack on Titan Gmork from The Neverending Story O-Ren Ishii from Kill Bill Vol.1 Lord Shen from Kung Fu Panda 2 And pretty much any villainous dragon from any movie.