Greed can make people act crazy. For example, in the story of the South Sea Bubble. People heard about the potential for huge profits in the South Sea Company and invested all their money without really understanding the risks. They were so crazy about getting rich that they ignored all the warning signs, just because there was a true story of some early investors making a fortune.
The Klondike Gold Rush is another case. Thousands of people left their normal lives and rushed to the Klondike region in Canada after hearing about gold discoveries. They endured extremely harsh conditions, like freezing cold and difficult terrains. Their craziness was driven by the hope of getting rich quickly, which was based on the true reports of gold being found there.
Yes, 'Crazy Heart' is based on a true story. It often draws from real - life experiences in the music industry, particularly those of aging and troubled musicians.