In regards to the cultural paradigm of moral obligation, as Rand lays out in The Fountainhead, if the pinnacle of the self in "service" or "duty" to one's fellow humans is the alleviation of suffering, then we in turn must desire that there continue to be suffering. Should suffering cease altogether, then we have undermined the very thing that permits us to achieve a state of social, moral, spiritual grace.
This can be described as a satisfaction of the moral ego, one where we endeavor to stand before our fellows and say, "Look how much suffering I have saved people from!" Selflessness becomes a badge we wear to gauge our dedication to society.
Selfishness, in contrast, can be determined to be the giving, fully and uncompromisingly, of one's purest state to society. In art, for example,it would be the unflinching conviction to make the thing that is in one's heart as it appears there and not censor it for the sake of not offending or upsetting the status quo.
I'm sure I missed many things, but I'm no literary critic, and ya'll can read the book.
It certainly has some polyamorous characters in it....