This quote speaks to the value of authenticity and introspection in a world often characterized by superficiality and noise. It suggests that there is nobility in choosing to be true to oneself, to simply exist in one’s own terms, rather than conforming to societal expectations or playing a role for the sake of appearances.

The "noisy, shallow actors" Thoreau refers to can be seen as people who are more concerned with external appearances and societal approval than with their own inner truth. They might be loud and attention-seeking, but their actions and words lack depth and sincerity. In contrast, choosing to "simply be" is about embracing one’s authentic self, even if it means standing aside from the crowd. It involves a certain level of introspection and self-awareness, as well as the courage to be different.

In today’s world, this idea is more relevant than ever. In the age of social media, where people often portray idealized versions of their lives, it’s easy to feel pressured to conform to certain standards or to seek validation from others. However, this quote encourages us to resist these pressures and to prioritize authenticity over popularity.

In terms of personal development, applying this idea might mean focusing on self-discovery and self-improvement rather than comparing oneself to others. It might mean pursuing one’s passions and interests, even if they’re not considered "cool" or "trendy." It might also mean standing up for one’s beliefs, even when they’re unpopular. Ultimately, it’s about finding and embracing one’s unique identity, and being proud of who one is, rather than trying to fit into a certain mold.