Designers are not users.

Good information architecture makes users less alienated and suppressed by technology. It simultaneously increases human satisfaction and your company's profits. Very few jobs allow you to do both at the same time, so enjoy.

In the attention economy, anyone trying to connect with an audience must treat the user's time as the ultimate resource.

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 are not designers.

The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.

Inadequate use of usability engineering methods in software development projects have been estimated to cost the US economy about $30 billion per year in lost productivity.