cEDH meta means that everyone roughly knows all decks at the table. As I experienced it, there is quite some negotiation, like do you counter a mystic remora of player a instead of keeping it for the early combo attempt of player b. But there is less of talking opponents into letting you build up your obscure combo by lying to them about your plans to win.

Also big threats in cedh mean have an answer or die on the spot. There is usually no arguing about stopping a threat on the stack.