This study investigates what atmospheric conditions are necessary to produce rainfall extremes in three different regions of Australia. It finds that it takes two to tango. In all regions the top 100 rainfall events in a 20 year period are characterised by a concurrent very high moisture content and strong upward vertical motion. Either of them alone is not sufficient to create an extreme rainfall event. This highlights the important interplay of the dynamics and thermodynamics of weather systems in making rainfall extremes. Understanding how extreme rainfall will change with climate change therefore requires us to understand how both moisture and vertical motion change as the planet warms.