The young clerk's responsibilities included bringing the judge a hot cup of coffee at the start of every day.
Each morning the judge was enraged that the coffee cup arrived two-thirds full. The clerk explained that he had to rush to get the coffee delivered while it was still hot, which caused him to spill much of it along the way.
None of the judge's yelling and insults produced a full cup of coffee, until he finally threatened to cut the clerk's pay by one-third if he continued to produce one-third less than the judge wanted.
The next morning he was greeted with a cup of coffee that was full to the brim, and the next morning and the morning after that.
Then, one day the judge(now pretty impressed) asked the clerk what new technique he uses to make sure the glass is always full?
The clerk says that it is simple. He just brings the glass 2/3rds full to the office and then fills it full with rest of the coffee which is in his mouth!