it allows for you to precisely focus on one part of a broad topic. It allows for you to be able to point out the minuscule details within a topic versus focusing on the broad topic of a whole.
I feel like he felt happy that he took the road because it had made all the difference. At the end there is a sense of melancholy but also excitement, the end is slightly unclear whether or not it is an simple impactful choice or how the author interprets the choice whose impact is unclear.