I have always put a lot of faith into the idea that you have the genes that can cause things, such as schizophrenia, and the way you are brought up determines whether or not that gene is "set off". I'm no scientist, but I studied psychology, so I'll give it a shot. Incest does produce bad genes, and how Joffrey, Tommen and Myrcella all look relatively normal is beyond me, but perhaps GRRM didn't want to go into that, due to lack of knowledge or whatever. I don't know how DNA is determined, but my best guess is that Joffrey got a lot of the bad traits from both Jaime and Cersei, and they developed into his personality because of the way he was brought up. If anyone does know more about DNA and genes, and the theory of traumatic event, please let me know. I love to learn.
Cersei is a terrible mother. Not only is it commented on by some characters in the books (Kevan springs to mind?), but it's glaringly obvious to me as a reader that she could have done so much more. She didn't let Jaime near her children, because of fears their parentage would be found out (though, as someone has mentioned in another thread, that could have been explained as Jaime simply being the twin of the childrens' mother, but there we go), and she said that Joffrey screamed every time Robert picked him up, which made him stay away as well. So, there we have three children without a decent father figure. Joffrey knew he would be king at some point in his life, so he was raised to think highly of himself, and to expect great things to happen for him in the future. He was also raised to believe that people should respect, fear and love him purely due to his position. Tommen and Myrcella were not raised in this way - nobody expects one of their children to die - so they were pretty much left to their own devices. I assume they were tutored by a septa like Sansa and Arya were, but I can't be sure because I'm pretty sure we aren't given much detail on their early lives. Joffrey was given the Hound to guard him (can we be sure at what age?), but not discipline him, so from a pretty young age he had a scary-looking man protecting him, but someone who would never harm him. I don't blame the Hound in any which way for the way Joffrey was, and if he stood by and let Joffrey do horrible things, again I can't fault him - it wasn't his responsibility to discipline the boy.
The cat incident keeps coming up, and I think it's very relevant to Joffreys' state of mind. Some people have noted that he was probably curious - yes, I agree that he probably was, but the length he went to to satisfy his curiosity is not normal. Holding a cat down and slicing its' belly open is no easy feat, especially for a child, so he must have applied a lot of pressure to still the cat. This incident brings to mind the idea that a lot of killers begin by torturing and killing animals, and I agree with it. When he was crowned king, Joffrey showed how vicious he could be. He could have been worse, I suppose, but he had some psychotic tendencies that are very worrying.
As for Robert, his reaction to the killing of the kitchen cat was a natural one, albeit not the correct one. He could have handled Joffrey in a much better way, and maybe Joffrey would have been better for it, but his natural reaction was to smack the child in disgust. The fact that Robert was a very big, strong man and hit Joffrey with such force that Renly thought he'd killed him is relevant, but it doesn't make Robert an abuser. If Cersei had let him, or hell, if Joffrey was
actually his kid, maybe Robert could have been a better father. It's mentioned that all his bastards' mothers loved him, and the bastards themselves thought very highly of him (Edric Storm for one).
Jaime could have had a good influence on Joffrey, again if Cersei had let him. He seems to speak kindly with Tommen, and I think he might have been a good father given the chance. Of course, I understand why Cersei didn't let him be a father, but simply being Uncle Jaime might have been enough to give the kids a strong father figure in their lives.
So, to summarise, my point is that a mixture of things lead to Joffrey turning out to be King Festering Boil (still love it!

) - but a lot of them come back to Cersei. No supervision; sun-shone-out-of-his-arse; no good, constant father figure; bad genes; the list goes on. I know people say that Cersei is given a hard time, and "everyone blames the mother", but for me as a woman, it disgusts me when women do not take care of their children. You essentially grew that child inside you, you carried it, nursed it, it is of your blood and it is your legacy. I treat my cats better than she treated her children. She is unduly harsh on Tommen, vicious even, yet she let Joffrey get away with murder (quite literally). As Queen Regent, surely she had more power than Joffrey when he ordered Ned to be beheaded? I thought that was why you have a Regent, so that the child-monarch cannot just make laws on whatever takes their fancy (didn't Tommen want to ban beets, or something?). She treated her children differently, and I know that Joffrey was the Crowned Prince but she brought him up in the complete wrong way, and let the other two go to shit in essence. It's just lucky that they probably had good tutors and their kind natures came through instead of the evil shown in Joffrey. As Zimbardo says, we all have it in us to be good or evil. And I read an old proverb recently, which I really liked. I just found it online, so I shall leave you all with it and be off:
Quote
An old Cherokee is teaching his grandson about life:
"A fight is going on inside me," he said to the boy. "It is a terrible fight and it is between two wolves. One is evil - he is anger, envy, sorrow, regret, greed, arrogance, self-pity, guilt, resentment, inferiority, lies, false pride, superiority, and ego. The other is good - he is joy, peace, love, hope, serenity, humility, kindness, benevolence, empathy, generosity, truth, compassion, and faith. This same fight is going on inside you - and inside every other person, too".
The grandson thought about it for a minute and then asked his grandfather, "Which wolf will win?"
The old Cherokee simply replied, "The one you feed".
Edited by Fire&Blood, 25 February 2012 - 06:08 AM.