Louis C.K. stopped by "Late Show with David Letterman" on Wednesday to promote his new HBO special "Oh My God," and explained to Dave why he doesn't take photos with fans -- and how his policy can backfire on him.
He told an anecdote where some women asked him for a picture, and he declined, but wanted to be polite and asked for their names.
"Then I see the two women give their camera to some guy to take their picture with each other," he said. "So then I look at the story from their point of view. They want a picture of themselves, then I said, 'I just don't like doing that. I'm so sorry. But what's your name?' What a creep!"
He also described his conflicting feelings about raising his daughters to be good people.
For instance, how to tell them not to lie: "Honey, your word is the most important thing. Don't lie, because lying only fixes everything. The truth is, lying fixes everything. Forever. It's like magic," he said. Letterman disagreed with Louie, perhaps exhibiting his own history of having a tricky relationship with the truth.
Check out the clip above, where Letterman makes Louie answer why he screamed "f*ck you, Letterman!" at the Ed Sullivan Theater in an episode of "Louie" last season.