Why was it unnecessary to create strong defense in the Ardennes Forest?

Creating a strong defense in the Ardennes Forest was deemed unnecessary because military planners underestimated the potential for a German attack through that area, viewing it as a difficult and less strategic terrain for large-scale operations. Additionally, the Allies believed their defenses along the Siegfried Line and in other areas were sufficient to deter any offensive. Consequently, the lack of preparation in the Ardennes contributed to the success of the German surprise attack during the Battle of the Bulge. This misjudgment highlighted the Allies' overconfidence in their defensive positions.