What factors affect stock exchange returns?

What are the key factors that influence the returns on stock exchanges? Are they primarily driven by market sentiment, or do economic indicators such as GDP growth, inflation rates, and interest rates play a significant role? How do geopolitical events and natural disasters impact stock exchange returns? Do corporate earnings and dividend policies also contribute to the overall performance of stock markets? And finally, how do investors' perceptions of risk and their willingness to take on more risk affect the returns they can potentially earn?