Like the most notable of cynical movie narrators, Travis Bickle arrives in “Taxi Driver” less an observer and more a force of nature nearing the breaking point of his stability. What separates him from a breed of other loners eager to critique the system is how far he is willing to go in dismantling it. This is not a man who gazes directly at the cultural construct of 1970s New York with pragmatism, and when he becomes driven to shake up its foundation, each choice plays like a step further away from a tangible moral center. In many instances that can be amusing to watch, at least when the results are uncomfortable rather than dangerous. Consider his interaction with women: early on he attempts to earn the interest of Betsy (Cybill Shepherd), a political volunteer for an aspiring presidential candidate. At first she is just as amused by his blunt worldview as we are, until their first date ends up in a seedy theater showing porno. Now contrast that to how he approaches Iris (Jodie Foster), a 12-year-old prostitute whose eyes seem to plead for him to save her – admirable, perhaps, if you were to just passively observe the behavior. But while his is a pattern that is the staple of many movie characters whose madness walks in the guise of noble intentions, rarely are they this frontal, or so pointed in arriving at the core of the crumbling psyche.