Final answer:
Sam's loss of her business due to exhaustion from working 80-hour weeks exemplifies a failure to understand the necessary level of commitment to sustain the business.
Step-by-step explanation:
The example of Sam closing her home-based consulting company because she was tired of working 80-hour weeks is an example of failing to understand the level of commitment required for a successful business. This involves underestimating the amount of time, energy, and resources that are necessary to maintain and grow a business. The error here is not primarily related to poor planning, ineffective use of employees, or the mishandling of finances, but rather to a personal decision driven by the cost to the owner's quality of life due to an overwhelming workload.