False. One of the initial assumptions of economics is that "rational people think on the margin". What this means is that people are rational if they consider the marginal costs and the marginal benefits of their decisions. At the time, if a person makes a choice, then they have calculated that the marginal benefits are higher than the marginal costs. However, they may think about the decision and learn later that it was not a good decision, however, at the time it was a rational choice. If people slow down their thinking when making important decisions and consider all the costs and benefits, they will make better decisions, although it is difficult to always have all the relevant information, which means that rational decisions might not always be "good".