In every single case, the Scooby Doo gang discover a human is behind the mystery, not ghosts or mummies or whatever. Yet they start each new case believing the villain is a supernatural being. Every time. Not once do they say “maybe it’s an old man like last time”
@JoParkerBear That would start to invite questions about continuity though, and I'm not sure the writers were paid enough for that responsibility 😆