It is not always by plugging away at a difficulty and sticking at it that one overcomes it; but, rather, often by working on the one next to it. Certain people and certain things require to be approached on an angle.

Arnold contrasts brute persistence with a more oblique, strategic intelligence. Some problems resist direct force: pressing harder can deepen resistance, narrow perception, or fixate the mind on an unproductive approach. Progress may come indirectly—by shifting attention to an adjacent question, changing the frame, or approaching through a related task that loosens the knot. The second sentence extends the idea from abstract “difficulties” to human relations and cultural objects: people and ideas have their own angles of access, requiring tact, patience, and lateral entry rather than confrontation. The remark captures a characteristic Arnoldian preference for balance, measure, and cultivated judgment over mere willpower.