as far as Lannisters go Him Jamie & tyrion are the best...I rather hate Cercie Tywin is a cold hearted basterd but he is a leader. Hes effective in what he dose and his moves are always planned out he knows how to secure alliances and chooses said allies more carefully then not. The man could be a good king if only he wasn't so freaking cold do he might prosper.
Because as a leader and an administrator, he's a rather capable person.
Also, a fictional character posesses traits that human person don't have. For example, an extremely nice person in real life would be liked by some many people, however, in fiction, said character would be a bland one.
Have you read the books? If you haven't, I think it's breefly mentioned in season one. Jaime wants Tyrion to have a woman, so he stages a rape, and makes it seem like he saved a peasant girl, Tysha from two rapists. He hands her over to Tyrion, who falls in love with her and marries her before the night is over. A couple of weeks later, Tywin finds out, cancels the marriage and makes Jaime tell Tyrion that Tysha was a whore. He then proceeds with letting his guards rape her for a silver each, and then he has Tyrion go last and pay a gold coin because Lannisters are worth more. Lovable guy you got there!
I know he also turned Shae agains't him slept with her too O.o I just said hes a cold bastard I don't like him cuz hes full of sunshines and rainbows. I like him cuz hes cold ruthless and even his own children aren't safe from his cold calculative nature.