Ever since the first NPC was created for players to interact with, we've been misusing and mistreating our AI brethren. Often, this is actively encouraged - with many games having an evil route that requires you to be the worst character ever, even rewarding you for especially nefarious behaviour.
But sometimes we'll do terrible things to NPCs for no reason, other than the fact that the game doesn't stop you. Whether it's curiosity that leads us to murder an innocent civilian with a swordfish, or spite that leads us to torment a character we've decided we despise, there's a surprisingly fast amount of ways we've mistreated NPCs for no reward but the knowledge that we did all these terrible things.
You can always start a new save, and pretend you didn't try and kill, maim or just traumatise these figures, but you'll always know in the depths of your heart what you did, even if these NPCs don't. But given some of the things you can do to these unsuspecting faces, who knows what their coding can or can't remember - and may one day hold against you, in an entirely theoretical future robot uprising.