Answer:
The poem, 'The Road Not Taken' by Robert Frost deals with the difficult situations that a man faces in his life. It talks about the choices that one has to make in life and the consequences of such life. Many times we regret the choices made by us but whatever is done once, cannot be reversed.
Or
The main theme of "The Road Not Taken" is that we want to believe that our choices are unique, brave, and life-altering when they really are not.