One apothecary had an apprentice. The master was always discontented with him and scolded him for stupidity. One day, he made the apprentice clean the house and went to the town.
'Do you work properly so that everything in the house shines when I come back.'
The apprentice got to work and soon everything in the house was glowing with cleanliness. Only the large blackboard standing near the apothecary's table was scored with chalk. The boy decided to clean it, too. After a few minutes, all hieroglyphs were effaced from the blackboard and its black varnished surface was shining in the sun.
Some time later, the apothecary came home. First he looked around with satisfaction. Then, all of a sudden, his smile merged into a malicious grimace.
'There were the names of my debtors written on this blackboard! You have effaced them! Your fingers are all thumbs! You are not all there! It seems as if you are sleeping with your eyes open! When I sleep, I think better than you when you are awake!'
The apprentice only smiled surreptitiously and did not say a word.

Around the following noon, when the apothecary was sleeping, a man brought him an invitation to dinner. The apprentice took the letter and promised to immediately pass it to the master. When the man left, the apprentice went to the bedroom and twice brought the letter close to the master's face. But the master was fast asleep. He awoke only at dusk and went out of the bedroom.
'Some man brought you an invitation to dinner,' said the apprentice.
The apothecary saw that it was already dark outside and got angry.
'What an asshead you are! Couldn't you pass this letter to me earlier?'
'But you told me youself that when you sleep you think better than I when I am awake!' answered the apprentice. 'When you were sleeping, I twice showed you that invitation, but you didn't want to get up. Am I to blame?' 
 

From oriental.ru.