Clearly it would be misleading to assign one sole cause (like the crash of '29) to the Great Depression. And while all the causes are valid, some are more interesting to examine than others because of the way they continue to shape our spending patterns
Relying on credit for purchases was a virtually new practice in the 1920s. Stretching out payment plans made the average American able to afford luxury items for the first time. However, buying an item on credit is not a payment as we all know--it is merely a promise to pay. Effectively then, every purchase on credit that we make carries a risk. What happens if we buy that expensive car, take out a student loan, etc., and then lose our job? Defaulting on a loan is equally bad for business as it is for the consumer.
SO....why did retailers do it? Why was the phenomenon of credit purchases so popular in the 1920s? Why do you think it is so prominent today, despite the fact that it proved to be a colossal mistake during the Depression?