Mormon faux pas...

I'd heard that only Mormons are allowed to enter Mormon temples. I asked my colleague, "how do they enforce that? How do they know?"

He pulls out a card. He's literally a "card-carrying Mormon." Thing is, there's no picture ID on the card and they don't ask for one.

"Theoretically, could you give the card to someone else?"

"Yeah, there are stories about that. Some temples have cafeterias in them. One guy apparently tells his non-Mormon friends that the food inside is good. He gets them in to eat. The plot was exposed when his friends started asking, 'where's the coffee?"

Why this is funny: see Mormon religious observances.