8 Video Games That Made You Regret Killing Bosses

Kingdom Hearts: 358/2 Days offers up some laser-guided regret the moment you kill your pal Xion. 

Xion suddenly initiates a battle with protagonist Roxas after revealing that she's a puppet being controlled by the villainous Xemnas, who has been planning for her to defeat Roxas, absorb his essence, and become a perfect copy of Kingdom Hearts' main protagonist Sora.

After an intense final boss fight in which Xion is defeated, she delivers a mournful dying monologue to Roxas, just as her body dematerialises and her heart joins Sora's. 

But the real crushing blow? As Xion dies, it becomes clear that all memory of her existence is being slowly forgotten by everyone - a fact that Xion herself is also aware of.

And if you're somehow not already sobbing, Roxas signs the whole sorry scene off by asking, "Who else will I have ice cream with?" as Xion's body evaporates into nothing.