Problem 1: Mostly, people want to avoid "overhead" or indirect costs, but as you can see, it is important to have support systems, building and insurance, human resources, etc. Most businesses would prefer to have no overhead, but it is a necessary part of business. After all, you have to have a building to have your factory in, you must have sales people, human resources, etc.
What other parts of the company would be considered "overhead"?
Problem 2: Each type of business has its unique types of costs. For example, an accounting firm will have direct costs of their accountants working on a project, but in any other business, accountants are considered "overhead"
What other examples can you give as to different costs that will be different when used in another type of business?
Problem 3: When you buy machinery, for example, it is not a "cost" in that period, it is depreciated over time and each month, a certain portion becomes "overhead" or operating cost.
Can you give examples of other things considered as overhead or operating costs?