The article represents a thorough analysis of the most important results obtained with the help of the Experience sampling methods (ESM) in the frame of the author's longitudinal studies. The author explores positive (not negative, as he traditionally supposed) correlations between the scores of the egoism scale (“good, benefit for oneself”) and the altruism scale (“good, benefit for other people”). He also explores a certain predominance of the egoistic scores over the altruistic ones in most life situations that have been estimated in the course of the explorations. Some mental experiments are also conducted. They help to follow possible perspectives of the different life choices. The author makes a conclusion that the overall summing of the individual egoistic benefit together with the altruistic use got by other people creates a maximal quantity of good - the value, which is traditionally studied by ethics. A combination (not an opposition as it was adopted earlier) of altruism and egoism in a productive individual activity responds to the characteristics of the ideal ethical formula, in which a personal and a social interest correspond to each other but are not identical. In the contrary, an individual will either have to fully submit his personal interests either to social ones (an altruism dominance), or choose a short-term hedonism as the main life orientation (egoism dominance). Both of the above mentioned perspectives are demonstrated as deficient. In the last part of the article, the author recommends to introduce the “rational egoism” (“rational altruism”) lessons at schools, where the pupils could discuss and practically participate in the disputable and complex life situations based on the discovered interaction between the egoistic and altruistic components of their behavior.