I'm sure it's different for everyone, but I don't buy the "each year is a smaller slice of your life" explanation. That would require a very cognizant recognition of the breadth of the span of your life. We can't be bothered to read a fucking newspaper, you mean to tell me we're grasping the complexity of the totality of our lives?
I think it has more to do with something King said; it's about living in the moment versus not. I remember working at the Hartford Civic Center as a security guard, and there was one shift that NO ONE wanted: it was the top of a stair well, and you literally had to sit on a folding chair in this 12 foot by 12 foot stair landing and make sure the "kids" didn't sneak in the door. In hindsight it was dumb as shit (anyone could have been rolled or rapes or whatever) but I always took it. I'd slip a paperback in my pocket and - before iPods and phones and shit - I would bring my little "Walkman" cassette player. The five hours was a welcome break; no school, no relationships, no work (you know what I mean), no nothing except me, my thoughts, my prayers (yes), my book, my music. And it still dragged, but it was a moment in time.
I'm exceedingly patient like that; I like myself, and have zero problem being alone. And yet, even I find myself fidgeting after a while. Where's my phone? Did someone try to get in touch with me? Did I miss a text? Did TAC post the results in that roulette? Did Trump say something stupid (again)? And with all that filling my minutes, I find that <SNAP!> it's Friday already.