Selfonomics is defined as the study of human behavior, individually and in groups, seen through the lens of self-interest. Various subtypes of self-interest (SI) are defined; Individual (ISI), Direct (DSI), Protective (PSI), Misguided (MSI) and Collective (CSI). Self-interest, all the time, fits 99% of data from the range of human behavior in all realms, including altruism, religion, everyday life, psychological problems, as well as economic bubble, health care and politics. Problems created by omnipresent self-interest are discussed, and possible solutions to those problems are offered.