Forget the best beverage. I can prove coffee is the most important thing for mankind with a statement.
"Now is Sunday night. Tomorrow is Monday morning. If coffee were outlawed/banned or what ever. How much of productivity will go down around the world, planes will fall from the sky. Sea monsters will raise from the sea bed, but people still sleepy will think they're dreaming. If zombies try to eat brains, they wouldn't know who's a zombie."