[nscalf]

I took this a bit differently, though in the same vain. The "unforgiving minute" I read as "every moment doesn't care who you are or what you do, it just marches on", and "sixty seconds' worth of distance run" as more of "put in work you're proud of for every second of each minute".

Essentially, there is no greater purpose or person giving you slack---if you can be proud of each second of each minute, the world is your own.

The differences in our interpretations of the poem is what makes it a great poem though. Both readings have very similar messages, and both messages are very impactful.