The fact that Tyrion, after so many years of things going against him, finally has a chance to be considered on his own worth.
When Pod arrives to Tyrion's manor in Braavos, Tyrion effusively and happily welcomes him.
Arya becoming Brienne's squire. Both for Arya (who has always liked the idea of learning how to fight) and for Brienne (who gets yet another person who thinks she's awesome).
Arya and Sansa's meeting again after several years being away from each other. Fittingly, it begins with a Call-Back (Arya throwing food at her sister).
The reveal that Ned and Cat were reunited in Heaven.
Sansa slowly falling in love with Tyrion.
The reunions among all the surviving Stark children.
When Tyrion is in a drunken despair after learning the truth about Tysha, it's Sansa who's able to comfort him and get him back to normal.
As Cersei's wallowing in despair as she's granted her wish to be a male warrior in Hell, Robert appears before her as a pregnant woman tending to her wounds. When it appears she's merely going to roll over and wait for the next round of punishment, Robert tells her of one of the few comforts damned souls such as they are granted: they can go to succor other fallen souls and try to help them go forth - and he's been trying to help Joffrey, however long it might take him. After a brief hesitation, Cersei pulls herself together and leaves her tent to help her son, showing her one redeeming trait - her love for her child.
The fact that Robert and Cersei aren't doomed to hell for all eternity. As revealed in Petyr's last chapter one CAN move on but they must realize what they did was wrong, accept they did wrong, and feel true regret. So while it might take centuries the two of them can become better and eventually move on.