Here is a different twist on an oldie but goodie.

An old veteran walks into a grocery store. Immediately, the cashier stops him and says, "sir, your barracks door is open." At first, he pays zero attention to her because he doesn't live in the barracks. So, he continues shopping until he spots a man stocking some shelves. He tells him what the cashier said and asks what she could've meant.


He tells the veteran that his fly is open.

After completing his shopping, he goes back to the same cashier and says, "ma'am, you told me my barracks door was open. While you were looking, did you see a Marine standing at attention, saluting?"

The cashier replies, "no, sir. I just saw an old, retired veteran lying on two seabags."

...