It is tempting to call this irrational. It is more useful to ask what it is for. Consider gossip. It is a small thing, and small things are where habits live. The lesson is modest. Build for the person who exists, not the one in the model. The remedy is rarely exhortation. It is a change to the situation so that the easier choice is also the better one.
Who should read it
We describe the departure from the model as an error. We might equally describe the model as a hopeful guess about us. Institutions know all this, of course, which is why gossip is so rarely left to chance. Economists have spent decades modelling trust as a quantity. It behaves more like a weather system. Every one of us runs the same shortcut, and every one of us believes we are the exception.
