From a friend who is a retired Soldier...

One sunny day in 2005, an old man approached the White House from across Pennsylvania Avenue, where he'd been sitting on a park bench.
He spoke to the Marine standing guard and said, "I would like to go in and meet with President Kerry."

The Marine replied, "Sir, Mr. Kerry is not President and doesn't reside
here."

The old man said, "Okay," and walked away. The following day, the same man approached the White House and said to the same Marine, "I
would like to go in and meet with President Kerry."

The Marine again told the man, "Sir, as I said yesterday, Mr. Kerry is not
President and doesn't reside here."

The man thanked him and again walked away.

The third day, the same man approached the White House and spoke to the very same Marine, saying "I would like to go in and meet with
President Kerry."

The Marine, understandably agitated at this point, looked at the man and
said, "Sir, this is the third day in a row you have been here asking to speak to Mr. Kerry. I've told you already that Mr. Kerry is not the President and doesn't reside here. Don't you understand?"

The old man answered, "Oh, I understand. I just love hearing it."

The Marine snapped to attention, saluted, and said, "See you tomorrow."