How is he normal? He's literally a sociopath. Ok, I guess sociopaths exist in RL, so it's...normal? I think it's hinted at very strongly in the books that Joffrey didn't just "turn" into a sadistic little cunt. Remember the story about the cat and it's litter of kittens, and why Robert punched him in the face? Torturing small, harmless mammals as a kid (with no realization you are doing anything wrong) is a pretty clear sign of being a friggin psychopath. No one needs to be taught to feel empathy on that level, it comes naturally.
He's based in reality, that's what I meant. Kafein said 'He has no motivation but evil itself, which makes him quite ridiculous and one of the weakest part of the books IMO.' I strongly disagreed with this as he doesn't seem at all ridiculous to me. There are plenty of people in the real world who, given too much power with no control, would do similar things as well. Heck just look at half the dictators that have ever been around. I remember that story, but some kids do shit like that. If they aren't taught what's right and what's wrong, which lets face it, Joffrey never has been because he's Cersei's precious little boy and Robert didn't give a crap, nor Jamie. There are some parts in the book where it's quite obvious Joffrey is just looking for attention, mostly from his father. And it's no real surprise he's as fucked up as he is.
Actually in that respect just need to look at the Mountain and the bastard. Both fucked up for the sake of being fucked up.
If Twyin was so good at politics, you'd think he would have a proper heir secured. Instead he originally failed arranging marriages for Jaime and Cersei (one to Rhaegar, I forget who Jaime was supposed to get), horrifically abused his third child Tyrion who could've been an excellent heir, got outmaneuevered by the Mad King (who permatrolled Tywin) in having his oldest child appointed to the KG, and also managed to never remarry after his wife (who was probably raped repeatedly by Aeron and this possibly gave birth to Tyrion) instead wallowing in depression and having no more kids.
Also the idea that he was such a good hand who kept the realm stable is pretty funny, considering during his rule the entire kingdom collapsed into civil war and his royalist side got destroyed. His gruesome slaughter of the Dornish royals during the sack of King's Landing led to them hating Lannisters permanently. Tyrells are already usurping all the domestic power in the capital on the TV series even. Now he just massacred the high lords of the North, further undermining his respect and crediblity for him and the Lannister name for generations to come. This is just being an idiot obsessed with short-term goals, with long term political consequences that will ruin their house.
Commander wise, he lost a battle to fucking Edmure Tully, the stupidest most inept person in the series (in the books, in the TV show the Mountain was leading the battle) His campaign in both versions against the North was just him getting trounced every time.
All he has is a lot of money and a lack of ethics. He isn't very intelligent, and
BOOK SPOILERSif you've read the books, everything he worked on hilariously falls apart instantly after his murder as a culmination of his vast amount of mistakes and lack of long-term planning or grooming any proper heirs or anything remotely successful except band-aid fixes of threats of violence. No better than a Bolton really, except Roose and Ramsay are way more entertaining
He was indeed a dick bag to Tyrion but in all fairness his wife died in childbirth giving birth to him, and a dwarf in this time period would have had literally no social acceptance whatsoever as you later learn about the lower born dwarfs in the book. Even less than now. For a powerful family to give birth to one would have been considered really unlucky/bad in a whole variety of ways. So in all honesty it's no surprise Tywin has always despised him. Not that I'm justifying it, just putting it in context.
Regardless, the other stuff is indeed correct. But at the current point he is the head of the most powerful family in Westros and has just gained control of huge swathes and knocked off his biggest opponent with some power play. If that isn't demonstration enough of his abilities I don't know what is. Furthermore, he wasn't the hand when Westeros descended into civil war. He gave it up after disagreement with the mad king. The mad king had a string of 'yes' men hands who he subsequently decided to knock off one after the other before finally doing what he did to the Starks. All of this was whilst Tywin was sulking in Casterly Rock and we all know he happily sat there until it was clear who the winner would be (also a smart move on his part).
The last bit in your spoiler I'll agree with definitely. He did lack for long term planning on that respect but will say no more because of spoilers