What are two common ways that cash can become an issue even if profit is not?

What are two common ways that cash can become an issue even if profit is not?
Cash can become an issue in the event of late payment by a customer leading to cashflow problems. Similarly, an unexpected and unbudgeted cost can lead to cash being an issue if the business does not have sufficient funds to cover the cost of, for instance, replacing a vital piece of manufacturing machinery due to sudden failure which could halt production. Retained profits within the business might be available to cover the shortfall however.