Any case where a character who comes Back From the Dead remembers nothing about the afterlife. Usually done to preserve ambiguity about what the universe's afterlife is actually like, but sometimes we actually see the character in the afterlife before they come back with no memory of it. Fridge Brilliance dictates that this makes sense. Even if the soul exists, there's no reason for memory brain cells to record anything if the Ghost in the Machine is elsewhere while experiencing things; it would be less explainable if they did remember. In some cases, it turns out they don't remember because there was nothing there, or there wasn't one at all.