When two people are speaking to each other about the same thing, but are not on the same wave length. They are both making the same point but think that the other misunderstands. This often ends in extreme bouts of laughter because both parties involved realize their stupidity.
A: I think we should go to the grocery store first because I need to get bread.
B: No! We need to go to the grocery store first.
A: I know, that's what I said.
B: No, you need to get bread.
A: But why would you want to go the grocery store first?
B: Because you need to get bread you just said that.
A: Hold on, let's just go to the grocery store first since we both want to go there first!
B:What a fail conversation we just had!