The false-consensus effect occurs when people assume that others think the same way they do, often viewing alternate responses as deviant and unusual. For example, if a designer loves using shortcut keys, they might assume that all users prefer shortcuts too and might design a software interface that relies heavily on these shortcuts.

However, not all users are comfortable with shortcuts and some might prefer navigating through menus. This assumption could make the software less user-friendly for those who aren't like the designer.

Because of this bias, it’s easy to mistakenly think that only someone very different or unusual could fail to figure it out. Recognizing the false-consensus effect can help you create products that cater to a wider range of preferences and needs and not just your own.