Travis Bickle constantly suffers from delusions of eloquence. He has a strong inner life but lacks the education and cultural background to give voice to it, and instead uses whatever phrases around him to suit his purpose, often coming across as a "square" (as Iris notes) or as a mix of a "prophet" and "pusher" (as Betsy notes). A key example is the lunch between Travis and Betsy where Travis says, "I gotta get Organi-sized" which Betsy sees as a sappy office joke but Travis takes it as serious wisdom, and in a Brick Joke, eventually puts that poster in his apartment. His general overall seriousness and total lack of a sense of humor and his Sarcasm Failure (in his conversations with Iris, Sport, Wizard and Betsy) are also a key part of his general social failure and his eventual breakdown. The conversation between him and Wizard is the ultimate example where Wizard more or less provides existentialist ideas as the word on the street picked it up in the 70s, and Travis more or less sees that as bull-shit and Wizard shrugs and admits he isn't Bertrand Russell and tells him You Need to Get Laid.