A bird in the hand
Once upon a time in a village far away there lived a wise old man. If anyone in the village needed an answer to a question that they could not find themselves, they would visit the wise old man, tell him and he would always give them the right answer.
Also in this village lived a young man who did not really think that the wise old man was clever. So he said to himself, 'He is not that clever, I am going to trick him into giving the wrong answer so that all the people in the village can see that he is not as wise as he makes out. I am going to catch a bird and go and knock on the wise old man's door and ask him, 'is the bird my in hand alive or dead ?'. If he answers 'alive', I will crush the bird dead. If he answers, 'dead', I will open my hand and let the bird fly away'.
So off he went and caught a bird and strolled up to the wise old man's door and knocked. The wise old man answered and asked the young man 'how is it that I can help you ?'. The young man said, 'wise old man, I have a bird in my hand, is this bird alive or dead ?'
The wise old man looked at the young man and thought for a moment before answering, 'young man, the answer is in your hands'.
(Traditional parable, seen on the wall of an exceptionally busy office).