I love digital queues. Why? Because I can move through them with ruthless efficiency. Queues empower me to consume and interact with enormous volumes of data in quick succession. Queues include, but aren't limited to emails, RSS feeds, tweets, Pocket articles, Chrome tabs, even my own blog posts on Draft.
Why do queues work? What's the magic?
Queues work because they're repetitive. Repetitive actions don't require thinking. When I'm working through a queue of content, regardless of the type of content, I can effectively ignore everything but the content itself. The queuing mechanism is so good that the mechanism itself goes away; all that remains is pure content.
For example, when I'm going through my daily feed of about 400 articles, I keep my finger hovering over the "next" button. My eyes stay fixed on the top of the screen. I can blast through headlines in less than half a second because my brain has learned to quickly read titles, process them, and make a lightning decision to skip them or dive deeper. This is only possible because I can repeat the same 2-3 steps in quick succession. If there was even the slightest variability - changing the font, the location of the headline on the screen, or moving the "next" button even half an inch, my productive would instantly drop 50%.
The same is true of emails and subject lines. I can process an email subject in less than half a second and decide if it requires additional thought or action. If it doesn't, I can archive it instantly. On the desktop, this requires pressing the "Delete" key, and in Mailbox on my iPhone, a quick swipe to the right.
This concept can be thought of more broadly across all forms of design. The more frequently a function or series of steps will be performed, the easier it should be.