The road not taken by frost

Consider Frost's "The Road Not Taken."  A common (mis)interpretation of the poem is that it's about taking the nontraditional path.  However, it seems to be more about a poem about rationalizing one's actions, as described in the video below.  After reviewing the video, comment on this tendency of humans to rationalize actions.  Why would this narrator tell a story where he/she clearly alters events?