What “mischief” does the speaker do?

The speaker’s “mischief” is to question why the neighbors keep repairing a wall when it serves no clear purpose. He wonders aloud, “Why do they make good neighbors?” and points out that his apple trees will not cross over to eat the neighbor’s pine cones. So the best answer is that he questions the tradition of wall-mending.

AI-written and checked against the verified answer.