When Jaime reunites with Cersei at the end of the episode and they die in each others' arms, I said, out loud, "You've GOT to be KIDDING me." That's how shocking and upsetting it was to see the redemption arc that the series has been building for Jaime dismantled in a single episode in such careless fashion. What was the point of having him strike up a (brief) romance with Brienne? Why did he ride North to defend the living? Why did he make such a show of abandoning Cersei in the first place? In the end, like most of the other storylines discussed in this post, this proves to be a colossal waste of time when he seemingly gets a brain transplant and flip-flops on his entire plan out of nowhere.
Yes, Jaime has always had an unhealthy addiction to his sister/lover/mother of his children. Game of Thrones has shown that time and time again, proving repeatedly that their relationship is nothing but toxic. She's his addiction. It's because of how well the writers have fleshed out the insidious, cyclical nature of their bond that makes Jaime's choice all the more disappointing.
His final scene with Cersei in the crypts beneath the Red Keep has a sheen of tragic romance to it; two lovers dying in each others' arms, unable to see anything other than their love and desire for each other. ("Nothing else matters. Nothing else matters, only us.") This is a grave disservice to Jaime, who we've seen pull himself out of his familial addiction and rise above, proving to those around him that he's truly a man of honour. In the last handful of seasons we've witnessed Jaime evolve into a new character entirely, one worthy of praise. Why would the showrunners have given him such a lame, unfulfilling death? Have we been watching different shows?