Jarrell's notable and influential essays on Frost include the essays "Robert Frost's 'Home Burial'" (1962), which consisted of an extended close reading of that particular poem, and "To The Laodiceans" (1952) in which Jarrell defended Frost against critics who had accused Frost of being too "traditional" and out of touch with Modern or Modernist poetry .
While a case could be made for the sigh being one of satisfaction, the critical "regret" analysis supports the interpretation that this poem is about the human tendency to look back and attribute blame to minor events in one's life, or to attribute more meaning to things than they may deserve.  In 1961, Frost commented that "The Road Not Taken" is "a tricky poem, very tricky," implying that people generally misinterpret this poem as evidence of the benefit of free thinking and not following the crowd, while Frost's intention was to comment about indecision and people finding meaning in inconsequential decisions.   A New York Times Sunday book review on Brian Hall's 2008 biography Fall of Frost states: "Whichever way they go, they're sure to miss something good on the other path.” 
Two roads diverged in a yellow wood,
And sorry I could not travel both
And be one traveler, long I stood
And looked down one as far as I could
To where it bent in the undergrowth;
Then took the other, as just as fair,
And having perhaps the better claim
Because it was grassy and wanted wear,
Though as for that the passing there
Had worn them really about the same,
And both that morning equally lay
In leaves no step had trodden black.
Oh, I kept the first for another day!
Yet knowing how way leads on to way
I doubted if I should ever come ...