Warning: spoilers below!
The Walking Dead followed through on its promise to kill off a main character during the season seven finale, and it'll take us a while to get over the loss. We speculated about who would be the victim, and we weren't surprised when Sasha took a hit for the team and turned herself into a walker in a last-ditch effort to screw over Negan. Looking back on Negan's mini speech to Sasha at the beginning of the episode, we should have seen it coming. Knowing what we know now, take a look at what he says.
"You are gonna help make sure things get back on track today. You are smart, hot as hell, dignified as sh*t, and you don't suffer one godd*mn fool. No one's gonna wanna watch you die; I don't wanna see that. So, you don't have to. But someone does. Maybe a couple of us, tops. But not you, and not most people. We are gonna help solve some sh*t."
Sasha does help things get back on track, just not for Negan. She helps "solve some sh*t" for Rick's crew, because that's where her true alliance lies. His compliments to Sasha, though twisted, are true. No one wants to see her die, and in a literal sense, no one does; we see her alive, then we see her once she's turned. Sasha dies in the coffin on her own terms, listening to music of her choice and protecting her family.
While Negan doesn't watch her die, she puts her death directly in his face. By taking the pill and attacking him, she may as well be saying, "Oh, you think I'm pretty and you don't want to see me die? F*ck you."
Hats off to the writers for this subtle foreshadowing.