A simple model is developed where total social happiness (naively defined as the sum of individual cardinal utilities) depends on the specific form of the individuals' utility function, and the size of the social group and on the distribution of goods and opportunities. Individuals are characterized by selfish, altruistic, envious or masochist behavior. We show that, under reasonable assumptions, total happiness : (i) increases with higher altruism; (ii) decreases with higher envy; (iii) increases with the reduction of inequalities in goods and the distribution of opportunities and viceversa;