7 Things A Song Of Ice And Fire Did Better Than Game Of Thrones
5. The Tysha Reveal
In the show, after Tyrion escapes from prison the night before his scheduled execution, he heads to his father's room and finds him sleeping with Shae, his prostitute ex-girlfriend. He attacks and kills Shae, then confronts Tywin. When Tywin insults Shae, calling her a "dead whore," Tyrion loses his patience, and kills him with Joffrey's crossbow.
The books include one key element that the show leaves out. Just after freeing his brother, Jaime decides to tell him the truth about his first wife Tysha. Tyrion married her thinking she truly loved him, but Tywin told him that she was a prostitute. Jaime reveals this was a lie that Tywin told to punish Tyrion for wedding below his station. Tysha had truly loved him, and he had spent most of his adult life thinking he was unlovable.
Taking away this revelation removes half of Tyrion's incentive to kill Tywin. We see less of how that Tywin has been tormenting Tyrion since well before the story began. In the books, Tywin's taunt that Tysha is "wherever whores go" sticks with Tyrion throughout his travels in Essos, and the show could have doubled down on his painful introspection had they kept in the truth about Tysha.