The document discusses the concept of "Homo Economicus" which assumes that humans act rationally and self-interestedly to maximize their wealth. It questions the validity of this assumption by presenting experiments that show humans may not always act rationally due to emotions, sunk costs, and other factors. While rational choices consider opportunity costs and maximize utility, humans can be persuaded against self-interest or make decisions without full information. The document also suggests that while economists apply rational self-interest to firms and governments, these groups aim to maximize profit and social welfare rather than individual utility.