“No Problem” is a problem.

The customer may be sarcastically thinking “I’m certainly glad my request for more coffee is ‘No problem.’ because I certainly don’t want to create problems for you.” If your goal is to enrich the relationship with the customer, then try substituting the lifeless, negative “No problem.” response with an enthusiastic, positive response like “I’d be happy to do that.” You can expect customers to be more appreciative of your service and more likely to reward you.