I'm struggling to fully understand what happens when the aggregate demand (AD) curve shifts in the economy. I know that aggregate demand represents the total demand for goods and services at different price levels, but I'm confused about what causes the curve to shift and how that impacts things like output, inflation, and unemployment. For example, if the AD curve shifts to the right, I understand that it means more is being demanded at each price level, but what exactly does that mean for the economy as a whole? How does this affect the balance between supply and demand, and what can policymakers do in response? Any explanations or real-world examples would really help me get my head around it.