Users spend most of their time on other sites. This means that users prefer your site to work the same way as all the other sites they already know.
Users will transfer expectations they have built around one familiar product to another that appears similar.
By leveraging existing mental models, we can create superior user experiences in which the user can focus on their task rather than learning new models.
Minimize discordance by empowering users to continue using a familiar version for a limited time.
Visually demonstrated by:
Relevant: Also known as “Jakob's law of the internet user experience"