You can’t just run back to the past because it’s familiar. It’s tempting, but it’s a mistake.
"For once, his father did what Tyrion asked him. The proof was the sudden stench, as his bowels loosened in the moment of death. Well, he was in the right place for it, Tyrion thought. But the stink that filled the privy gave ample evidence that the oft-repeated jape about his father was just another lie. Lord Tywin Lannister did not, in the end, shit gold.”
A Storm of Swords, Chapter 78; Tyrion XI.