Self-interest should be differentiated from the popular notion of "doing whatever one wants." The latter phrase is highly ambiguous and offers no guidance toward achieving one's authentic self-interest. On the one hand, we might say that a person does what he or she "wants" simply by acting to attain his or her maximum subjective value. As we shall observe in our study of praxeology, however, subjective value is always maximized, and hence the pursuit of subjective value can hardly constitute an ethical precept. On the other hand, the phrase "doing whatever one wants" might be interpreted to mean guidance by one's feelings. As was already noted, however, one's feelings are not in general a reliable guide for determining what is good for one's life (p. 3.3:2).

Self-interest encompasses long-run as well as short-run considerations. Rational men and women will choose to undergo short-term discomforts or to forgo short-term comforts, if such choices are anticipated to result in their long-term well-being. They do not regard such temporary deprivations as "sacrifices," because they maintain an awareness of the total context.