Mine would be gunning down a group of children in Fallout 2 in the Den, who were throwing rocks during one of my killing sprees. Or when I left a woman in KoToR 1 searching for the rest of her life for a droid she'd never find.
Off topic: A bit later, after convincing the inhabitants of Modoc to massacre the Slags, I talked to their leader and he said 'We killed everyone, even the children', just before Michael Corleone (I was watching the Godfather on my TV as well) bellowed 'In my bedroom! Where my wife sleeps! Where my children come and play with their toys'.
And yes, I checked whether this has been done before.
Off topic: A bit later, after convincing the inhabitants of Modoc to massacre the Slags, I talked to their leader and he said 'We killed everyone, even the children', just before Michael Corleone (I was watching the Godfather on my TV as well) bellowed 'In my bedroom! Where my wife sleeps! Where my children come and play with their toys'.
And yes, I checked whether this has been done before.