The characters were one-dimensional and lacked any real depth or complexity. Travis Bickle, in particular, was a frustratingly flat character whose motivations were never fully explored or developed beyond a surface-level understanding of his mental illness, loneliness, and violent tendencies.

The film's attempt to portray Travis as a sympathetic anti-hero was unsuccessful, as his actions and behavior were often inexplicable and lacked any real nuance or depth. The supporting characters, including the object of Travis's affection, Betsy, and the young prostitute Iris, were equally one-dimensional and failed to add any meaningful depth or complexity to the film.

Additionally, the film's themes of violence and mental illness were handled in a shallow and exploitative manner, without any real exploration of the complex societal and psychological factors at play. Taxi Driver to be a frustratingly shallow and poorly executed film that fails to engage in any meaningful way.