In Taxi Driver,
after failing to assassinate the senator, Travis Bickle goes to save the underage hooker. I understand that he is angry and furious, and kills everyone to save her as some sort of redemption, and also for the pleasure of unloading his rage. He ends up surviving and being made to look like the hero.
Things go well for him, and Betsy (which he used to like) goes to his cab. Did she now want to restart things with him since he was a famous hero? That was my interpretation. Or does the scene have some other purpose (possibly, simply a coincidence)?
In the end of the ride, he doesn't charge her and drives off. Was this a way to reject her, since she was just changing her mind because he was famous? Again, my interpretation was that he would've asked her out if he was still interested.