Mental Model

The internal idea a user carries of how something works and the set of expectations they bring with them before they've clicked anything.

People don't arrive at your site empty-handed. Years of using other sites have taught them where the search box lives, what a shopping cart icon means, and that a logo in the corner goes home. When your design matches that mental model, the site feels obvious. When it fights that model, the site feels strange even if it's technically fine. User research and usability testing are how you learn what model your users already hold, so you can work with it instead of against it.