Martin Scorsese confirms that Taxi Driver’s most famous scene was nearly ruined by producers. Starring frequent collaborator Robert De Niro, Scorsese’s gritty 1976 portrait of a disturbed New York City cabbie won the Palme d’Or at the Cannes Film Festival, and today is still regarded as one of the master filmmaker’s best movies. Among the film’s iconic moments is an oft-imitated scene that sees De Niro’s Travis Bickle practicing his tough-talk in front of a mirror, as he prepares himself for the acts of violence that explode in the film's shocking climax.

https://screenrant.com/taxi-driver-movie-scene-change-producers-explained-martin-scorsese/