When you're sat at your computer gazing at its screen it's easy to get bored and start looking at a smaller screen until you get bored and start looking at a computer screen and then get bored and...
This is the modern-day infinite loop of self-distraction. But, as Randall Munroe points out, there's nothing particularly new about this kind of phenomenon:
"Ugh, today's kids are forgetting the old-fashioned art of absentmindedly reading the same half-page of a book over and over and then letting your attention wander and picking up another book."
Some things never change. They just get represented by pixels instead. [XKCD]