"No, she got it" replies the man. They both remain silent for the rest of the session, after which the psychiatrist proceeds to charge the man $60 for it.
Anti-humor is a type of indirect humor that involves the joke-teller delivering something which is deliberately not funny, or lacking in intrinsic meaning. The practice relies on the expectation on the part of the audience of something humorous, and when this does not happen, the irony itself is of comedic value.