Regardless of the project you are working on, and irrespective of the field you are in, the day end belongs to the end point consumer of your product or services as they are the main source of revenue for you. Whatever the product you produce and services you provide, they might fly up through various channels but finally they reach the customers in the market. If you are in the field where there is no role for the third party operator, and you are directly in contact with the clients and customers, then you are the sole ambassador of your company and your product.
When you come to directly deal the customers, then there are always some complications and middle way negotiations that you have to make. No matter how pulling and teasing the client may be, you have to develop your acumen to tolerate all such things. No matter how much the situation is dragged, you are always taught to be focused on the points of your concern.