The oxymoron of Military Intelligence
Armando Iannucci tells the story about why so many families were being shot to pieces by Allied troops at checkpoints in Iraq. Apparently the familiar western hand-signal (arm in the air, palm facing away from you) that means 'Stop' to most of us actually means the complete opposite to those in that part of the world. As a result unknowing civilians would be cut to ribbons after seeing the gesture and accelerating towards the barriers. This is of course an unfortunate and tragic misunderstanding - the real stupidity however is that it took 18 months for anyone to realise the mistake.
"If we know the enemy is open to attack, and also know that our men are in a condition to attack, but are unaware that the nature of the ground makes fighting impractical, we have still gone only half-way towards victory" - Sun Tzu, On the Art of War