For some, the concern stems from this line of thought: "This is my one life, and after its gone I'll never get it back. I need to make the best of it."
So then we imagine what the best life could be. We don't even have to try hard to imagine the best life - examples of people who had a better life are constantly made apparent. Whether a life more noble, more enriched, more fun, more profound, or any other adjective, it doesn't matter because we see them all.
Then we see that elements of our life are not notable and we regret that others may have done something better than ourselves. And then we feel guilty, sad, upset, or angry that our ONE CHANCE, our life, isn't what it ought to be in order to be the best.
So, we trudge on making the best moves we know how. Its sometimes a bit of relief to see articles like this which, for a few minutes, give a sense of relief that maybe we don't have to cram every ounce of our lives with greatness... I don't buy it though.
This is my one chance, and I'll be damned if I waste my most functional hours of the day on something that doesn't matter.