I divide my officers into four classes: the clever, the lazy, the industrious, and the stupid. Each officer possesses at least two of these qualities. Those who are clever and industrious are fitted for the highest staff appointments. Use can be made of those who are stupid and lazy. The man who is clever and lazy however is for the very highest command; he has the temperament and nerves to deal with all situations. But whoever is stupid and industrious is a menace and must be removed immediately!

Kurt von Hammerstein-Equord (1878-1943) German general
(Attributed)

Possibly apocryphal. Quoted (unconfirmed) in Horst Poller, Bewältigte Vergangenheit. Das 20. Jahrhundert, erlebt, erlitten, gestaltet [Conquered Past. The 20th century, witnessed, endured, shaped] (2010). Sometimes cited to Truppenführung [Troop Leading] (1933), the German Army Field Manual, but not found there. Also attributed to Erich von Manstein.