Quote from : D-Day, June 6, 1944: The Battle for the Normandy Beaches Book

No matter how bad things got, no matter how anxious the staff became, the commander had to “preserve optimism in himself and in his command. Without confidence, enthusiasm and optimism in the command, victory is scarcely obtainable.” Eisenhower realized that “optimism and pessimism are infectious and they spread more rapidly from the head downward than in any other direction.” He learned that a commander’s optimism “has a most extraordinary effect upon all with whom he comes in contact. With this clear realization, I firmly determined that my mannerisms and speech in public would always reflect the cheerful certainty of victory—that any pessimism and discouragement I might ever feel would be reserved for my pillow.