There is a book from HCL CEO, it says customer comes second. As he says because the employee comes first.
This true, as if you take care of employee then employee will take care of customer.
There is one saying, you have to earn creditably, before we ask him or her for extra payment. We have to do value-add to the customer. You have to start walking, before you run:)
It is always our duty to ensure customer is satisfied. And then only we can ask for extra.
How well, we understand the customer, will be helpful in building revenues and credibility.
For example, simple task may be creating a web site for the customers. If the requirement is only web site creation, if customers gets the backend admin screen as part , that will be great success story for the organizations. It will be extra bonus, if we provide customer lifetime support:)