In the earlier scenes, Stan sounds like any of us,lol including me, on our most self doubting, self conscious days, regarding that woman at the gym.....There is something to be said for social grace, and tact, but ask her out already! Everyone's gone through that phase, though Stan is like 20 years too old for that, though I suppose 15 year or so of marriage, plus ugly divorce will do that....
Edit: at later gym scene, oh, for sure, there's something off with that....
Final scene and that dinner, were tense, uncomfortable, borderline disturbing.
What's so dark about their relationship with Paige is that, they are both ruthless killers. Clearly, they would never kill their daughter, but every time they sense she's a liability, it's just natural thought, logically, they use killing as a problem solving tool. Paige is a problem. That's the kind of emotional darkness the show excels in.