Spoilers ahead — don't read if you haven't seen the season finale of Game of Thrones, "The Children."
Happy Father's Day, Tywin! Westeros's winner of the father of the year award was finally killed by one of his children, and with good reason. Well, reasons — of all of the Lannisters, Tyrion had the most cause to get rid of dear old dad, who seemed to love his legacy more than any of his actual children, even if he did let them live in luxury. Let us round up all the motives, scores to be settled, and lingering grudges that would make Tyrion shoot a crossbow bolt at his father on his "throne."
1. Tywin nearly killed Tyrion (as a baby). When Tyrion was born, he committed two crimes in his father's eyes — he was born a dwarf, and he was the cause of his mother's death during labor. Neither Cersei nor Tywin ever let Tyrion forget that they blamed him for Joanna Lannister's death. Cersei called it a cruel joke, that he "ripped [our] mother open on your way out of her and she bled to death." Tywin, who was a little less colorful, still made it clear that he could never forgive Tyrion, "you who killed your mother to come into the world." On top of his mother dying during childbirth, Tyrion was a "monster," which the family barely tolerated. "I wanted to carry you into the sea and let the waves wash you away," Tywin admitted to Tyrion. "Instead, I let you live and brought you up as my son, because you're a Lannister." But even before admitting that, Tyrion sensed that he owed his life to being born into a rich family. "If I had been born a peasant, they might have left me out in the woods to die."
2. Tywin nearly killed Tyrion (as an adult). During battle, he assigns Tyrion to be in the vanguard with the hill tribes. Even though he was unskilled in the ways of war, Tyrion recognizes it as a suicide mission. "Surely there are ways to have me killed that will be less detrimental to the war effort!" he protests. When he's sent to meet the Dornish party arriving for the royal wedding, even Bronn recognizes it's a dangerous assignment. ("Just in case the Martells are looking to spill some Lannister blood, might as well be yours, ay?") Later on, during his trial for the murder of King Joffrey, Tyrion recognizes that it's a farce. "I know that one of my three judges has wished me dead more times than I can count, and that judge is my father." Even if Cersei is to blame for stacking the evidence against him, Tyrion knows that his father won't give him a fair trial, and he doesn't trust that his father would honor any agreement to let him join the Night's Watch. He partly asks for a trial by combat to screw with his father's plans.
3. Tywin denied Tyrion's inheritance and refused to recognize him as his heir. Although Tyrion is the second son, his elder brother Jaime gave up his rights when he joined the Kingsguard. Tyrion asks to be Lord of Casterly Rock, and Tywin tells him no. "Men's laws give you the right to bear my name and display my colors, since I cannot prove that you are not mine ... I will let myself be consumed with maggots before mocking the family name and making you the heir to Casterly Rock." Ouch.
4. Instead, Tywin gave Tyrion jobs that felt like insults, and insulted him outright when he managed to do well, despite being set up to fail. First, Tyrion was put in charge of all the drains in Casterly Rock. When he was named Master of Coin on the Small Council, he at first protested ("I'm quite good at spending money, but a lifetime of outrageous wealth hasn't taught me much about managing it") but then learned how to manage affairs quite quickly. He saved the crown "hundreds of thousands" by splitting the cost with the Tyrells for the royal wedding, only to have that news dismissed by his father. And when he was first told to sit in as Hand of the King, Tyrion was shocked. "Why not my uncle? Why not anyone? Why me?" he asked, stunned that his father would have any faith in his abilities. And to his own surprise, he was actually good at it — so Tyrion wanted to keep on doing it. But just when he'd achieved his biggest accomplishment, organizing the city's defense during Blackwater, his father swooped in at the eleventh hour to reclaim the position for himself, got all the credit, and acted as if Tyrion had done nothing. "I gave you real power and authority. You chose to spend your days as you always have, bedding harlots and drinking with thieves," Tywin says when Tyrion asks for "a little bloody gratitude."
5. Tywin was weirdly fixated on Tyrion having sex with prostitutes, and was especially cruel to Tyrion's first love, who may or may not have been a whore. "It turned out badly, so [I] never let [myself] love again," Tyrion explains to Bronn and Shae. He tells a story about Tysha, who was running away from would-be rapists, when he and Jaime encountered her on the road. "Jaime scared away the men easily enough while I wrapped her in my cloak ... I took her to the nearest inn and fed her. I forgot how afraid I was around girls, how I was always waiting for them to laugh at me, or look away embarrassed, or ask me about my tall, handsome brother. I forgot everything but Tysha ... By morning, I was deep enough in love to ask for her hand." Instead of getting the marriage annulled (because Tywin didn't want Tyrion married to a peasant girl), he had Jaime tell Tyrion "the truth" — that he had arranged the whole thing to help Tyrion lose his virginity. And then Tywin handed over Tysha to his guards to be gang-raped.
"I would have killed the man who did that to me," Bronn tells Tyrion upon hearing this. But instead of killing his father, Tyrion just continued to seek the company of prostitutes, which is why when we first met him on the show, it's in Ros's first brothel. Until he meets Shae, he drinks from sundown to sunup, visiting three brothels a night, according to Varys. No wonder Tywin feared Tyrion would turn Casterly Rock into a "whorehouse." But his threat to hang any prostitutes he finds in Tyrion's bed seem excessive, no?
6. Tywin tried to force Tyrion to rape Sansa Stark. What else do you call arranging the marriage of a 14-year-old prisoner of their house and insisting that Tyrion get her pregnant right away? Even Tyrion, who is prone to all manner of sexual perversions, wants to draw the line at having sex with a child whose life has already been made miserable by other Lannisters. "That's cruel, even for you!" he tells his father. He can't bring himself to do it.
7. Tywin fails to visit Tyrion when he's injured from the Battle of Blackwater. "I'm sure he loves me dearly, as any father loves his child, his baby boy, yet he hasn't come to visit once," Tyrion complains. "I lay here, my face split in half, but father never came. My beloved father who somehow forgot to visit his wounded son." Being ignored by his father during his recovery seems to hurt him more than the injury itself.
8. And finally, the insults that make Tyrion feel like a "constant disappointment." (Wouldn't being ignored would be better than all the verbal abuse?) Tywin calls him a "lecherous little stump," "a stunted fool," "an ill-made, spiteful little creature, full of envy, lust, and low cunning," and "the lowest of the Lannisters." Sure, some of that is not in his hearing, but imagine growing up with someone who despised you so, and considered you a disgrace to the family name. Both of Tywin's sons are captured by the Starks at separate points, and in both instances, Tywin responds with military force, but he evidently cares more about his elder son. When Tyrion returns, Tywin barely looks up. "The rumors of your demise are unfounded," he tells Tyrion, who quips, "Sorry to disappoint you." Tyrion thanks him for going to war over him, and Tywin coldly retorts, "You left us no choice. The honor of the house was at stake. Your brother would never have submitted to capture so meekly." When Jaime is taken prisoner shortly, Tywin roars, "They have my son!" Even Tyrion realizes that his own capture didn't inspire any emotion — if Tywin ever intervened on his behalf (with the Starks, sometimes even with Joffrey), it's not because he cared about Tyrion, but because he cared about the possibility of Tyrion's future children. If Tyrion hadn't found the crossbow, that's one more way he could have had his revenge — just don't have any kids. Let the Lannister legacy die. That would have just killed Tywin.