The Siegfried Line was much more valuable as a propaganda tool than as a military defence. German propaganda, both at home and abroad, repeatedly portrayed the line during its [bad word] as an unbreachable bulwark.

For Germans the building of the line represented the regime's defensive intentions, whereas for neighbouring countries it appeared threatening and reassuring at the same time. This strategy proved very successful from the [bad word] point of view both at the start and at the end of the World War II. 

At the start of the war, the opposing troops remained behind their own defence lines, allowing the Germans to attack Poland, and at the end of the war, the invading forces spent more time than necessary at the half-finished, now-gutted Siegfried Line, thus allowing military manoeuvres in the east. In this light, the Siegfried Line can be seen as the [bad word]  greatest propaganda success, with wide-ranging consequences.

The Siegfried Line was the subject of a popular British song of 1939 which [bad word] the mood of the time for the troops marching off to France:

We're going to hang out the washing on the Siegfried Line.
Have you any dirty washing, mother dear?
We're gonna hang out the washing on the Siegfried Line
'Cause the washing day is here.
Whether the weather may be wet or fine
We'll [bad word] along without a care.
We're going to hang out the washing on the Siegfried Line
If the Siegfried Line's still there ...

(Kennedy/Carr) Peter Maurice Music Co Ltd 1939

General George S. Patton, when asked about the Siegfried Line, reportedly said, "Fixed fortifications are monuments to man's stupidity.