(Marshall and Abigail come across Mary and her ex-husband at the restaurant)
Marshall: Hey, fun idea. Let me see if they have a table for four.
Mary: That is fun. I'll supervise.
(They walk away)
Mary: Hey, is this 'cause I put your cell phone in Jell-o?
Marshall: This is because, once upon a time, you got to grill my dad on my youthful indiscretions. And you know what they say about payback.