What created these "good time"? Princeton University's Larry Kudlow explains:
Coolidge’s vice president was former Harding budget director and Chicago banker Charles Dawes. Coolidge kept on former-President Harding’s Treasury man, Andrew Mellon. Working with a Republican Congress during the mid 1920s, these men continued the “return to normalcy” policies of Warren Harding by cutting tax rates, reducing federal spending, and lowering the post-WWI Federal debt.
The timeless economic truths hold: lower taxes, reduce government debt, and people will prosper. The good times of the 1920's ended with the Great Depression - a time marked by increased government debt, higher taxes, and government interference in the free market. It is debatable whether or not regulation caused the Great Depression - some economists think that the reason is to be found in the tariffs - but it is in any case clear that the Great Depression was prolonged by government spending, government debt, government regulation of business, and taxes.