Never reheat with toppings already on. I learned this when I tried to microwave a potato with sour cream and bacon bits. Big mistake. The sour cream turned into a weird, watery mess, and the bacon became chewy and sad.
Always reheat the potato naked. Think of it like a canvas. You wouldn’t paint over a wet painting, right? Reheat plain, then add your butter, cheese, chives, or whatever makes your heart sing after it’s hot.