He goes around the base to give things an inspection, hoping he can make a few changes to improve things. Only half way through his inspection, he finds a private stood next to a bench, seemingly doing nothing.
Commander: Private, what are you standing around for?
Private: Sir! My orders are to stand here and make sure nobody sits on this bench, sir!
Commander: …Why?
Private: I’m not sure, sir! I was just told to do this by the previous commander!
Utterly confused, but unwilling to let the mystery lie, the commander makes a call to the previous commander, now promoted to brigadier.
Commander: Brigadier, sir. I just gained control of Fort Naimheer, and I was wondering why you ordered a man to stand next to a bench and tell people not to sit on it.
Brigadier: Oh, that guy? Yeah, I didn’t give the order to begin with. I just figured the other guy had a reason for it, so I left it alone.
Now even more confused, the commander makes contact with the general who led the base before him.
Commander: General, sir. I just gained control of Fort Naimheer, and I was wondering why you ordered a man to stand next to a bench and tell people not to sit on it.
General: Huh? Oh, that? It was a standing order. Before my time, you see.
Commander: Figured as much. Do you know who first issued the order?
General: Oh, I believe so. He’s retired by now, but I could get you in contact with him.
Finally, the commander makes contact with the veteran, a former commander like himself, who first made the order.
Commander: Hello, sir. Sorry to interrupt your retirement, but I just gained control of Fort Naimheer. Is there a reason why there’s a man standing next to a bench and telling people not to sit on it?
Veteran: …Is the paint still wet?
Poor guy has been carrying out his orders flawlessly for multiple commanders and is still a private. Someone give this guy a promotion.
Nah, he’s exactly where you want him.
A private is expected to follow orders, and he’s shown that ability in spades.
What he has not shown is initiative, which is expected from noncoms.
Does he deserve one, though? He hasn’t done anything useful, he’s just been standing next to a bench.
I’ve always viewed that joke as a biting criticism of tradition.
Oh, it absolutely is. Tradition for tradition sake leads to so many bad practices.
There’s a not entirely implausible chain of events from this private guarding the bench to a post-apocalypse cult centered around that same very bench.
