The following quote came up on Hacker News in the context of a discussion of Adam Curtis' blog post on MI5 and MI6. It comes from General Kurt von Hammerstein-Equord, German officer from the First and Second World War, an implacable enemy of Hitler.

This is how he classifies his men :

I divide my officers into four groups. There are clever, diligent, stupid, and lazy officers. Usually two characteristics are combined. Some are clever and diligent -- their place is the General Staff. The next lot are stupid and lazy -- they make up 90 percent of every army and are suited to routine duties. Anyone who is both clever and lazy is qualified for the highest leadership duties, because he possesses the intellectual clarity and the composure necessary for difficult decisions. One must beware of anyone who is stupid and diligent -- he must not be entrusted with any responsibility because he will always cause only mischief.

Stupid and lazy :

Curtis' post looks at some MI5 and MI6 history and is not impressed. From the post, E.P. Thompson on Chapman Pincher, a journalist :

"A kind of official urinal in which ministers and intelligence and defence chiefs could stand patiently leaking."