My father used to say "busier than a cranberry merchant." We never really knew why until my brother learned in an engineering course that for a long time cranberries presented a problem in food processing. How to get rid of the spoiled cranberries without a lot of onerous hand sorting?

Then somebody figured out that good cranberries bounce and spoiled once don't. Thus canned cranberry sauce was born. Until then, a cranberry merchant had to act fast to sell all his inventory. Hence, "busier than a cranberry merchant."