"DAVID ORR: He claims that he wrote it because he used to go on walks with the English poet Edward Thomas, because Frost spent a brief time in England. It was actually the beginning of his career as a poet.
And what he would like to say at readings afterward is that he and Thomas would go on these walks, and then Thomas, who has a somewhat more romantic sensibility than Frost, Thomas would always regret whatever path they had taken.
And then afterward, he would say, well, we really should have gone to the right. I could have shown you something over there. We should have gone to the left. I could show you something over there.
And Frost was very amused by this. And so he wrote the poem as a kind of joke at his friend’s expense."
In other words, it's more about regret than making the right choice, or that you deceive yourself sometimes by dwelling on a choice that is actually perfectly random. Or a million other interpretations...