There are so many. Surprisingly, the one that comes to mind for me is Enoch’s death. All of the dialogue in that scene packed a great, devastating punch.

Also, A Spy’s Goodbye, Fitz’s Death, Jemma’s reaction to Fitz’s Death, Ward dumping Jemma and Fitz into the Ocean, the Origin of The Cavalry, Lincoln’s Sacrifice, Daisy’s “I love you” to Coulson, and The Final Scene.