Every one of us runs the same shortcut, and every one of us believes we are the exception. The lesson is modest. Build for the person who exists, not the one in the model. In the studies we have, the effect is modest, reliable and almost entirely ignored by the people it describes. Understanding people turns out to be a more urgent task than changing them, and a great deal harder.
Three kinds of mistake
The strange thing about the school run is not that it exists but that it works, most of the time, for most people. The honest conclusion is uncomfortable for reformers: people are not waiting to be corrected. The measure that matters is not what people say about loyalty but what they do when nobody is scoring. A pattern this consistent is not a character flaw. It is a design feature, and design features can be worked with.
