Nobody sets out to be governed by the to-do list, yet it shapes an astonishing share of the ordinary day. Consider the to-do list. It is a small thing, and small things are where habits live. Every one of us runs the same shortcut, and every one of us believes we are the exception. It is tempting to call this irrational. It is more useful to ask what it is for.
The ordinary case
It is tempting to call this irrational. It is more useful to ask what it is for. Understanding people turns out to be a more urgent task than changing them, and a great deal harder. The lesson is modest. Build for the person who exists, not the one in the model. There is a version of this essay that ends with a policy prescription. This is not that version; the mechanism is interesting enough on its own.
