I admit I am a happy-family-utopia kinda player but this one time it took a turn.
Once a sim of mine cheated with a younger woman. They met at a bar and went back to her place. She was kinda coo-coo. Her house was all pink and flowery - even the lighting was pink - it was almost eerie.
Turns out she wanted him to leave his wife and children for her, but for him she was just a one time, heat of the moment kinda girl.
This is where my version of "dark gameplay" begins. I figured out that they could take n*des and found it absolutely hilarious (I mean it's a thing you can do in-game w/o cheats so it must be EA approved). She took a bunch of him, and he was posing all proud and stuff, I nearly fell off my chair. I made her put the photos all over her house to complete her utter insanity. I wanted her to use the photos to blackmail him, but couldn't find a way to implement that in gameplay, so she just became a background character with a dark and dirty secret all over her pink walls.