For the "Heckler" segment, Louis C.K. did not tell the audience in the comedy club that the heckler was an actress and they thought that the scene was real.
The confrontation with the heckler was based on a real-life experience of Louis C.K.'s. Earlier in his career, C.K. saw a heckler disrupt an audition for Late Show with David Letterman (1993). After he confronted her onstage, the heckler confronted him after the show. C.K. told the woman that he took the comedians' dreams away but the heckler was indignant and did not apologize.
The part where Louie meows at the cat in the store was not scripted. The cat belonged to the real owner of the store and the propmaster asked if the cat could be used in the scene.
Sylvia Kauders reprised her role as the old Jewish lady from American Splendor (2003) harassing the cashier about the price of the merchandise.