Your users don't remember the experience. They remember two moments of it.

In one of Kahneman's best-known experiments, participants held a hand in painfully cold water twice: once for a fixed stretch, and once for that same stretch followed by a slightly less painful extension. Given the choice of which trial to repeat, most people chose the longer one — the one with strictly more total discomfort — because it ended on a less painful note.

Kahneman called this duration neglect: the length of an experience has almost no bearing on how it's remembered. What sticks is the peak — the single most intense point, good or bad — and the ending. Everything in between gets compressed into almost nothing.

The long middle of a workflow — the repetitive form fields, the routine steps, the parts your team spent the most time optimizing — is exactly the part duration neglect erases first. That doesn't mean the middle doesn't matter; a slow or broken middle can absolutely become the peak. It means smoothing an already-fine middle by another few seconds buys you very little in what people actually remember.

What people do remember: the worst moment in the flow, and whatever screen they were looking at when they left. Both are disproportionately worth your design attention, relative to how much attention they usually get.

Most products treat the end of a flow as a formality — a plain confirmation toast, a generic "success" state, sometimes nothing at all. The peak-end rule says that's backwards: you can't always control where the peak lands, but you can almost always control how something ends, and the ending does a disproportionate amount of work in deciding whether someone comes back.

This is the actual reason small celebratory moments — the kind you've seen after sending a newsletter or finishing a purchase — earn their keep. They're not decoration. They're the last data point the brain uses to file the whole experience away.