Narcissism is a key theme in Infinite Jest and Mary K. Holland's subsequent essay on the same.
In an essay titled "On Narcissism: An Introduction", Freud argued that narcissism is a formulation of an individual's ego, or self-conception. In infancy, a child is unified with the mother - the mother providing for all the child's needs - which, in this egoistic state, leads the infant to conceive of the mother as part of himself. However, after the child leaves infancy and the external world intrudes in the form of the id, the child is forced away from this narcissistic state.
Thus, according to Freud, narcissism is an aspect of the individual's desire to retain and return to this internal ego. In the same way, as the mother is an aspect of the loop the infant perceives of needs and need-fulfillment, narcissism can manifest in the desire to return to this state of perfect fulfillment, and thus return to the ego. This is the promise offered by the Entertainment in Infinite Jest, which portrays the return to the infantile state and the apology for that endless return.