I've been using Kindle for Mac to read some eBooks that don't exist in print, and I have discovered a setting that I really like. I call it "Isolation Mode".
It's best described as Full Screen Mode, but it has some extra benefits for me: It blocks out everything else on the screen. No clock, no page numbers, nothing. Just you and what you are reading.
On of my weaknesses is that the competitive corner of my brain, once it is aware that I have finished two-thirds of a book, wants to crash through the remainder as if I am racing someone to the end. Comprehension doesn't matter, Being Done does.
Without page numbers, or the horizontal progress bar, or even the feedback a physical book can deliver keeps the competitive streak at bay, allowing me to focus on the ideas in the book. That's a huge bonus for me, but probably wasn't an intentional design consideration.