We were forced online for this session and during the classic "Wait, I can't move my token" "Here, let me sort this out for you" moment, I realized I had control of... a torch.
I've never seen someone else play D&D without being absolutely baffled at what kind of rules they use.
Come to think of it, it's not that rare to play a game like Settlers of Catan or even Uno with new people and also find that they have been following completely made up rules without realizing it.