All my friends are dead moment #1: Cinna's death is finalized in this book. It was brutal watching him dragged away in book two and we knew the moment was coming. But nothing said grim like hearing that Cinna, the calm support throughout the other two novels finally bit the bullet. Cinna was just the beginning though and the other two deaths were the hard hitters that had people questioning the ending so much. And then Boggs dies, right as you're really getting to like him. Way to drive the knife deeper.
All my friends are dead moment #2: Finnick. He just haaaaad to marry Annie only chapters before and we just haaaaad to get way too attached to him. His character was one of the best fleshed out through the story. In book two, we aren't sure what to think of him until the ending. But his scenes in book three are so memorable and brave that you can't help but love him. Between his selflessness with Annie and the way he helps Katniss through her difficulty knowing Peeta's being tortured make him the stand out character he is. But what divides the fandom is the way he died. His character deserved more than lizard mutt chow. And he kind of gets glossed over as a toss in. Oh hey, yeah. Finnick's dead. Realistic, yes. Unfair, hell yes.
All my friends are dead moment #3: Everyone knows this one. Because the ENTIRE series was built around saving her. Oh, Prim. We knew you were screwed the moment Suzanne Collins started building your character up a lot in book three. Her death was heartbreaking, not only because she was Katniss's entire reason for living, but because it also splintered Katniss' friendships and remaining family. The mother ditches her (way to go, deadbeat mom) and Gale, being the one who might've been responsible for the killing bombs, goes off to another district never to be heard from again. But. I see what you did there Collins. Symbolically, Prim was Katniss' whole reason for living and part of surviving trauma is finding a new reason to live. So Prim ultimately had to die in Katniss' transformation as a character as part of shedding the past and creating her own life.