I’ve found one of the most important components of performance is the perception. Within reason, the actual performance doesn’t matter as much as how people perceive actions to be progressing and completing.
This is about the user’s experience.
Consider the two possible experiences of loading a web page. In one version – the browser waits until all content is loaded. The other version – the browser progressively loads content, as we’re typically used to. Which one will feel faster, less frustrating, and more “productive”?
Are you doing the same in your app? Luke W explains it well in his post about content loading spinners.