What users believe they know about a UI strongly impacts how they use it.
A mental model is what we believe to be true. It is not always the truth. Our mental models are generally based on our experiences. It affects how we assimilate new things into our existing knowledge.
Individual users may come to your website with unique mental models. It’s okay if they don’t really understand how it works, if it simply works in a familiar way.
Make an interface simple as possible for your users to understand–even if that simple understanding is completely inaccurate.
Mental Models by Jakob Neilsen