Quote from Chandler in The One Where Ross Is Fine
Bill: What? Where did you hear that? Owen: He told me. And he paid me 50 dollars not to tell. Chandler: Which, technically, now you should give back. Colleen: You told him he's adopted? Chandler: I'm so sorry. But you should have a sign out there or something. Or at least whisper it to people when they come in the door. "Owen doesn't know he's adopted, and he also thinks Santa is real." Owen: He isn't? Chandler: We have to get out of here, baby.