When you've run out of reasons or explanations to your actions, you simply state, "Prove it!." It proves to be the "end all, be all" stumpers to all those not so complex arguements.
**Your finishing move to this phrase is immediately walking away after stating, "Prove it!"**
Dude, you drank the last cold beer. Prove it!
Why are you such an ass all the time? Prove it!
That's not cool making money off your own friends.Prove it!