Where a character displays a complete lack of understanding about culture, behaviour, social norms or other things that they should, by their own backstory and the world they live in, know. They don't have a plausible Fish Out of Water excuse like Time Travel into the past or future, or just arriving on a different planet, or even another country -- they should know this stuff already. However, due to the Rule of Perception, if the audiences don't know about it, someone has to explain it. May be used when Deliberate Values Dissonance would be far more plausible.