Common usability issues that are uncovered during testing include:
User interface clarity is often an issue because it is hard to know what should be included on a screen and how to lay it out in a way that is easy for users to understand. Navigation can be confusing because there are often multiple ways to get to the same place and it is not always clear which way is the best. Controls can be unintuitive because it is hard to know how to use them without prior knowledge or instructions. Workflows can be poorly designed because it is hard to know how users will actually use the feature. Design can be inconsistent because different parts of the user interface may be designed by different people. Error handling is often an issue because it is hard to anticipate all the ways users might make mistakes and design error messages that are helpful.