A rabbi and a priest meet up after a year not seeing each other.
The rabbi goes: "Man, you've put on some weight since last time!"
Priest: "Yeah I know, it is a new technique I came up with. You go to a restaurant, eat as much as you can. When the bill comes, you tell them you already paid for it."
Rabbi: "Sure, but the waiter won't believe you, right?"
Priest: "Of course he won't. That's when you tell him how dare he doubt a man of faith? It usually works and you can leave without paying."
Rabbi: "Very nice, I'll be trying this."
Later that day, the rabbi goes to his favorite kosher restaurant. After eating 5 plates, the waiter comes up to him with the bill.
Rabbi: "Oh, I already paid."
Waiter: "
Mmm, I'm pretty sure you did not sir."
Rabbi: "You know I'm a rabbi, how dare you doubt a man of faith? I told you, I already paid."
Waiter: "So sorry sir, you are right, it must be some misunderstanding, you're good to go."
15 minutes goes by and the rabbi is still at the table. 30 minutes... 45 minutes... 1 hour and he is still there! The waiter walks up to him: "Sir, why are you still here?"
Rabbi: "Well, I'm waiting for the change!"