Chesterton's fence
G.K. Chesterton · The Thing · 1929
You inherit the running of an old estate. Walking the grounds, you come upon a fence cutting straight across a path, fencing nothing in around it: it plainly serves no purpose and gets in the way. Your first impulse is to have it torn down. An old hand stops you: "If you don't see what it's for, I certainly won't let you destroy it. Go and find out why it was put there. When you come back and tell me you've understood, perhaps I'll let you remove it." The story holds for far more than a fence: a law, a custom, an institution whose use escapes us.
Faced with an inherited rule whose reason you cannot see, what do you do?