In Michael Dobbs’ “Saboteurs: The Nazi Raid on America” (which only briefly touches on life in Nazi Germany), he mentions Nazi spies-in-training who visit a pub in Germany in 1942. They get drunk and begin singing patriotic American songs like “The Star-Spangled Banner.” The author states that, while singing the anthems of an enemy country with might seem suspicious, by that point, regular German citizens had lost a grip on reality. They had been indoctrinated to believe that if the Nazi guards the spies drank with weren’t arresting them, the behavior was not to be questioned.