Ted Levitt's book called "Total Customer Concept" describes a phenomena regarding basic human behavior and a desire for heightened service levels. He urges vendors (service providers) to move towards “The Outer Limits” of their serving potential.

Levitt described four levels of potential for vendors.

GENERIC LEVEL: the provider delivers basic out of the box service, with nothing extra offered other than a basic product or service; with no commitment as to when that product or service will actually be available for purchase or user.

EXPECTED LEVEL: At this level the hours of operation and basic support requirements are defined.

AUGMENTED LEVEL: This level sees the service provider increasing their standard service offering in an attempt to provide more options to existing customers and to entice new customers into a buying pattern.

POTENTIAL LEVEL: This is the ultimate ‘shopping experience’ for the customer that relates closely to the excitement needs of customers (Kano).  At this level nothing is an issue for the provider to deliver to the customer, there are attractive purchasing options, heightened support available and an experience that sets a new benchmark for the customer in terms of true service delivery.
 
It is at the "outer limits" of service excellence that customer loyalty and retention can be created. This is where the provider actually controls the customer perception and leaves nothing to chance. The secret at these outer limits is the attention to minor detail; each detail on its own being relatively insignificant; but when pooled with all the other minor details a powerful force is created.

HOWEVER, service providers who strive for these outer limits must ask one VERY, VERY important question. Is the level at which I seek to deliver my products and/or services SUSTAINABLE?

If it is not, then while you reap short term rewards the withdrawl of these “minor details” due to cost cutting and low profits in the future will cause agitation amongst your customer base, abandonment and even complaint.