Henry's charactrization by the author in Red Badge of Courage is done through the thoughts Henry has. He is always referred to as "the Youth," and what he feels and thinks is narrated, unless he is engaged directly in a dialogue. He is the main character of the book and the novel tells his growth from an immature teenager to a war-weary adult.
The meaning is that being positive will get to a lot more places and you will get more things being positive. If ur negative all the time u will amount to nothing.