The U.S. economy has a seasonal cycle with strong growth in the second and fourth quarters, a big drop in the first quarter, and a small drop in the third quarter. This cycle changed over time, especially during the Great Moderation period. Real economic measures like output move in a similar pattern to the seasonal cycle. The reason for this similarity is that key economic indicators like GDP and stock prices also go through "bubble-like" growth and "crash-like" declines. Changes in people's preferences and how goods are made drive the seasonal cycle, while fluctuations in the discount factor play a bigger role in the overall business cycle.