'Louis C.K' originally intended for Parker Posey to play his therapist. But after meeting with Posey, he wrote a different character specifically for her.
Louie (Louis C.K.) tells Liz (Parker Posey), "I want you to know that I'm aware that you're young and beautiful and I'm not either of those things." In fact, C.K. is only about fourteen months older than Posey.