Here's a breakdown of the different elements:
* Reflective: The speaker is looking back on a past decision and considering its implications. He uses the imagery of the two roads to represent choices in life.
* Wistful: There's a sense of longing for what might have been, expressed in lines like "I shall be telling this with a sigh / Somewhere ages and ages hence." The speaker hints at a feeling of missing out on the path not taken.
* Melancholy: This is subtle, but the speaker acknowledges the weight of the decision and its potential consequences. The line "Two roads diverged in a yellow wood" creates a sense of solitude and uncertainty.
However, the poem also has a subtly optimistic undercurrent. The speaker ultimately chooses to focus on the positive aspects of his chosen path, and he believes it's been the "better" choice.
Ultimately, the tone is left somewhat ambiguous, allowing readers to draw their own conclusions about the speaker's state of mind and the true impact of the road not taken.