This question was posed by Robert Fost to his wall-mending neighbor in a poem titled "Mending Wall" written by Frost in 1919. Though the infamous line from the poem is "Good fences make good neighbors," if one reads the entire poem, one realizes that Frost questioned the whole fence making enterprise. An excerpt from the poem, courtesy of bartleby.com : My apple trees will never get across And eat the cones under his pines, I tell him. He only says, "Good fences make good neighbors." Spring is the mischief in me, and I wonder If I could put a notion in his head: "Why do they make good neighbors? Isn't it Where there are cows? But here there are no cows. Before I built a wall I'd ask to know What I was walling in or walling out, And to whom I was like to give offence. Something there is that doesn't love a wall, That wants it down!" I could say "Elves" to him, But it's not elves exactly, and I'