NOTE: The outline below is nothing more than a fun, informal introduction. It's merely an attempt of playing with the process of creating a proof, the arguments presented below will be like that of a young child.
The argument presented is as follows. You want a cell phone but your parents claim you can't have one because you don't have enough money to pay the bill and you might run-up their bill (you could also use you are not old enough). How are you going to prove to them that this statement is not true. Or in essence, how can you prove that you do, in fact, have enough money for a cell phone.