The first 5 minutes of Taxi Driver are the most important because they explicitly present the story and characters which is required in order to understand the rest of the film.
The film revolves around Travis Bickle, and his first scene introduces him as being an insomniac ex-marine. Additionally, there are slight subtleties that illustrate how lonely and separated from society he is. For one, he prefers to work long night hours as opposed to day hours. Thus, he isn't a very social person because he would most likely spends his day sleeping. Secondly, it appears that he isn't very appealing as a person because he isn't articulate. For example, he makes a joke to his interviewer about his conscience, but the interviewer gets frustrated. Travis replies "sorry sir didn't mean to uh --" Bickle can't finish his sentence, & he appears to be frustrated at himself because of that.
Much of Bickle's characterization has been revealed by the tone of his voice. However, his characterization is also portrayed by the content of the dialogue itself. From it, the audience learns that he was an ex-marine who most likely served in the recent Vietnam war. Additionally, Bickle's dialogue reveals that he isn't in tune with his social culture. The interviewer asks him if he's moonlighting which is slang for finding a second job, and Bickle is clueless to what that means.
Bickle's loneliness is further depicted when the audience is taken into his apartment. A long pan reveals how disorderly his home is.
The first 5 minutes of the film depict Travis Bickle very thoroughly in order to establish the film's focus. The focus is clearly of this inarticulate, disorganized, and lonely man who is not a real member of modern society. This character focus recurs throughout screenwriter Paul Schrader's films because he studied existentialism while he was in school. The film also explores how war may have affected a soldier's life after it ended. This pertains to the film's socio-cultural aspect because the film takes place and was filmed soon after the Vietnam War ended.
The importance of this extract is that it addresses Scorsese's theme that his modern society was a complete wreck after the Vietnam War. He did this by portraying a former soldier as a lonely, unintelligent, and socially awkward man who simply didn't not understand the world around him anymore. This was conveyed through Bickle's inarticulateness, his disorderly apartment room, and his dialogue with his interviewer. Additionally, this extract exemplifies the Film Noir Genre because the scenes are very gritty and utilize dark lighting in order to create a solemn tone that emphasizes the character's characterization.