At the beginning of the poem, the speaker finds himself at a point of decision - which road should he take? Deeper than the obvious choice of which way to travel, this reflects an individual in the autumn of life trying to determine a direction for the remainder of that life; to follow the commonly traveled path or "the one less traveled by."
The speaker recognizes that either path has merit. There is some desire to be able to travel both paths, but the speaker realizes only one path can be traveled at a time and that s/he probably would not be able to revisit this place in the road (or in life) and choose to take the path not chosen in the poem.
Eventually, the decision is made to follow the path that has not been used as frequently. The speaker understands that this decision will make "all the difference" in the remainder of his/her travels, and his/her life. There is some regret ("telling with a sigh") at not being able to experience the other alternative, but I interpret the poem as reflecting acceptance of the decision that was made.
we do this one in 9th grade here in india, from what i can remember, i reckon its based his not having taken the easy way out of his problems, and having fought his battles ethically.
it later turns out that he is not proud of it, because those who got to travel on "the road not taken" by the poet, reaped rewards and enjoyed life despite of having been the bad ones in this case.
he says that to always be good is not the best thing to do as your result is what matters and no one really cares about how you get there on the top, what matters is that you do or you dont. (not to be applied in real life please)
therefore it is about his struggle and failure to be the best despite of having been a hardworker, a true person.
----i hope it helps, cz thats how we learnt it----