We usually pretend that it's unexpected, unwanted, and entirely unnecessary.
I'm beginning to disagree.
After all, isn't this inclination to run nothing more than a distraction from the rest of "real life?" By my understanding, the running habit is the definition of a distraction, as it draws attention away from other, probably more important aspects of our day.
But that's where the paradox presents itself. It has been my experience that the more we run, the more we can focus on what's important; the very act of distracting ourselves allows for a level of discernment.
This effect is even layered within our runs. For example, when some rather large flying insect decided that dive-bombing my arm was a good idea, it was something of an annoying distraction momentarily, but this distraction was quite quickly diverted into a focus on getting back into the rhythm of the run, which, in turn, enhanced the focus on the non-running side of life.