I'm building an NCO
A lieutenant was out walking one day, and came upon a little boy, playing with a pile of shit.
"Son, what are you doing?" asked the lieutenant.
"I'm building an NCO," said the boy.
The lieutenant, thinking this was quite funny, returned with his captain, and asked the same question.
Again, the boy replied that he was building an NCO.
The captain, also thinking it was funny, went back to the ship, and brought the chief out.
Again the question was asked, and the reply was the same.
The chief then asked the boy why he was building an NCO.
The boy replied "Because I don't have enough shit to make an Officer."