It's actually not hard. Rationality is a form of communication. Its purpose to persuade other people and coordinate group activity, e.g. hunters deciding where

It's actually not hard. Rationality is a form of communication. Its purpose to persuade other people and coordinate group activity, e.g. hunters deciding where they should hunt and making arguments about where the prey might be. In that setting, rationality works perfectly well because humans are quite good at detecting bad reasoning when they see it in others. Because of the assumptions of psychological individualism, rationality is misunderstood as a type of cognition that guides an individual's actions. To a certain extent, this is a valid approach because incentives within organizations encourage people to act this way. We reward individual accomplishments more than collaboration. But many cognitive biases disappear when you aren't working under the assumptions of psychological individualism. For example, in the artificial limitations of a lab, you can show that people are unduly influenced by irrelevant factors when making purchase decisions. But in reality, when a salesperson is influencing someone to spend too much on a car, people say things like "Let me talk it over with my wife." We instinctively seek out an environment of social communication and collaboration where rationality can operate. Much of the advice about how to be individually rational comes down to simulating those conditions within your own mind, like scrutinizing your own thinking as if it was an argument being made by another person. That can work, but the vast majority of people adopt a more straightforward approach, which is to simply use rationality as it was designed to be used. Rationality is hard, but only for a small number of "smart people" who live in an individualistic culture prevents them from using it in the optimal way.