she actually fell for jon and when he "betrayed" her that was it. i dont think she wanted to do this from the beginning. shes been pushed in this direction. if jon would had never told her i think she would of held it together. once jon told her then didnt heed her warning about telling sansa and arya she was done. she had lost everything basically.

i saw a meme where they showed dany walking in the throne room when it was snowing back in the early seasons. turns out the snow was really dust.

this episode had me excited to see them winning, they destroyed euron and all the crossbows and that golden army. they had cersei corner, justice was coming.

then dany lost it. i guess in her head she saw this was the only way for her to maintain control.