ANSWER: Visual elements and customization.
Step-by-step explanation:
The visuals are very important in any app. However, good visuals in productivity apps are even more important because they create a more welcoming space for the users. This is surprisingly motivational.
The high customization element should exist in every productivity application. It wouldn't be pleasant for the user if there was only a light mode, for example, or only one theme that had many flowers when someone didn't like it.