The money to pay for them has to come in at the right time so it can go out at the right time. Some of that money may be profits, some may be borrowed capital, and some may be raised by selling stock. Balancing all that activity is part of cash flow. By managing your personal finances you already act like a business. Customers are the source of sales.
Customers are very important.
Keeping them happy is essential to survival. Everyone contributes to customer service in some way. The size of a company is often measured in terms of its total Sales or total Assets. Size is not a measure of efficiency or profitability. Changes in performance from year to year show trends.