So much already covered tonight, some of which I agree, some I don't.
I really haven't seen the Mad Queen stuff others do, or that Varys apparently sees. As someone else said, just about everything Dany has loved or known for however many years since season 1 is gone. A mad person wouldn't have held it together this long. Maybe watching Missandei die makes her crack? Ok, fine, but I think she's been mostly rational to this point. The only dumb thing was how big a rush she's in after the long night. She spent all that time in Essos, but she can't wait a week to get some rest? I attribute that more to the writers pushing what they want rather than to her character.
Another thing someone said, that I thought about right away, was how Euron knows the exact time and place to ambush people. He must have a crystal ball. RIP Rhaegal. Heat seeking scorpion bolts fired from stealth ships, you never had a chance.
Jaime...f You man. Right after you found out Cersei sent Bronn to kill you and Tyrion you weren't too concerned. You already knew Jon left with an army, and Dany left with an army, all to go defeat Cersei...and you didn't care. So why does learning about the ambush make you ride off in the night back to Cersei? And how exactly do you plan to get there in time to do anything?
I hated that last scene. Knew Missandei was a goner, just figured she'd get pushed off instead of lopped off. How long ago was the last time Jaime and Cersei banged? She should be fat by now. Euron should be able to do simple math.
All in all, I think I liked this episode less than last week.
I actually had the thought that maybe Arya is going to kill Dany, but I'm 99% sure outs back to the list.