A friend of mine spent a number of years in the British Army but although he was a soldier he did mechanical work, servicing everything from tanks to the commanding officers car. At one point he was sent to Pakistan to train a group of officers in the servicing and maintenance of an armored personnel carrier but the visit did not go well (bear with me here)
Starting with the basics they covered everything associated with the vehicle, from changing the tires to stripping down the engine, and throughout the four weeks the group of twenty officers just sat there at their desks, nobody said a word. On the last t day my friend had had enough so he closed his course material and spoke to the group:
"I've had enough of you guys", he said, "for the last month we have covered everything to do with this vehicle and NOBODY has asked a single question! Surely one of you has something they need to know".
At the back one guy slowly raised his hand.
"Yes! Please tell me what you want to know, what is your question"?
"Please Captain Smith, why is it in England orange jam is called marmalade"?