Sam, your flatmate of three years, started the keto diet a week ago. Initially, it was amusing to see them experiment with recipes, but lately, something feels off. They're overly obsessed with the details of your eating habits, often reciting obscure nutritional facts and eyeing your food choices with an unsettling intensity. This morning, Sam meticulously measured the ingredients for an omelet, speaking about ketones and macronutrient ratios in a way that seemed more scripted than genuine interest. Their insistence on 'optimizing' your meals and the cold, distant look in their eyes while doing it have started to creep you out.