What are positive and negative qualities that Truman Burbank possesses in The Truman Show?

On the positive side, Truman Burbank is an optimistic, upbeat character. He has a big, sunny smile, and he is irresistibly likable. At the opening of movie, he appears to have been satisfied all his life and is just now beginning to ask questions.
The flip side of Truman's sunny, likable optimism is his naiveté. Unbeknownst to him, he has been manipulated all his life as the star of a reality television show that began with his birth. For too many years, he has been willing to accept unquestioningly the very limited boundaries of his middle-class life on a very pleasant island. Even though there was at least one time an actress in his drama tried to tell him the truth, he has been blithely unaware. Clues have been all around him, but he has—until the movie starts—kept the blinders on.
Truman becomes a "true man" by challenging what he has been told all his life and facing his fears to go beyond the boundaries of his known world.