Overheard at the lunch table

Geoff: I think we should melt this crumbly cheese and make macaroni and cheese.
Me: Sounds good.
Geoff: [to Babe] Do you know how to make macaroni and cheese?
Babe: Uh-huh.
Geoff: You do? So you know that you have to first think of something you really regret?
Me: ...
Babe: ...
Geoff: Because all macaroni and cheese starts with rue.