Conversations with Weston: I don't always tell the truth

I just told Weston a story about an 8-foot tall man with bright green hair named Mr. Pixie. In the story, Mr. Pixie wants to go to Jupiter but is too tall to fit in Weston's rocket ship. Weston and his friends Pippi, Mr. Nilsson, Tom, Jerry and George are retrofitting the rocket so Mr. Pixie can go on an intergalactic cruise. Weston's mom calls him for dinner but he tells her that he needs to keep working so Mr. Pixie can fit in the rocket, and she says okay.

Weston: Does she know Mr. Pixie?
Me: No.
Weston: Then why does she believe he's real?
Me: Because Weston told her, and she knows he tells the truth.
Weston: I don't always tell the truth.
Me: What do you mean?
Weston: Sometimes I tell you I washed my hands but it's not the truth.
Me: Why would you do that? It's important to tell me the truth.
Weston (very matter-of-factly): Because I don't like to wash my hands.