Robert Frost's "The Road Not Taken" does, indeed, reveal directly certain emotions: regret, indecision, decision, doubt, rue.

A much-discussed poem in which Robert Frost creates an intriguing ambivalence, there is also, perhaps, the light satire of Frost's friend Edward Thomas, with whom the poet walked frequently. As they trekked along various paths, Thomas would worry that perhaps another way might be more pleasurable as it could contain more flora and fauna. This indecisive man would never be content as he walked because he was always anxious about other choices that could have made.

• indecision, doubt

The speaker's hesitancy about which "road" to choose is indicated in the first two stanzas as he surveys the paths that diverge in a fall woods. In the second stanza, the words "and having perhaps the claim," "Because it was grassy...," and "Though as for that...."  indicate the speaker's indecision.

His doubt is also expressed in the second stanza as the speaker remarks that the two paths are both "just as fair" and worn "about the same."

• regret, rue

Regret is demonstrated in the third stanza as the speaker is disappointed that he has not gone down the other path: "Oh, I kept the first for another day!" And, he "doubted" that he would get the opportunity to return and go down the other path. 

In the final stanza, the speaker indicates that he rues his choice of paths--"I shall be telling this with a sigh"--and this decision has had a profound effect upon his life, an effect that he wishes were different:

I took the one less traveled by,
And that has made all the difference.

In the words of A. E. Housman, the speaker feels "With rue my heart is laden."

Does "The Road Not Taken" reveal any attitudes or emotions?

Let's look at some subtle clues in the poem for attitudes and emotions: 

"Sorry I could not travel both / And be one traveler" The speaker wants to live his life to the fullest extent, and if he could, he would travel both paths. However, he is realistic about his limitations, and he does not allow these limitations to ruin his experience, instead accepting certain aspects of life. 

"Just as fair / And having perhaps the better claim / Because it was grassy and wanted wear" The more attractive prospect is the one that is less used, indicating that the speaker is excited by the idea of adventure and discovery.

"Oh, I kept the first for another day!" The speaker does not disparage people who disagree with him, thereby taking the more commonly used path. He is accepting and tolerates difference. 

"Yet knowing how way leads to way / I doubted if I should ever come back" This is not the speaker's first journey, and although he expresses a desire to return and take the other path as well, he is wise and experienced enough to recognize that this may never happen. However, he is willing to sacrifice this path for the infinite paths he has not yet encountered.