A mainframe computer on which everyone in the office depended suddenly went down.
They tried everything but it still wouldn't work.
Finally they decided to call in a high-powered computer consultant.
He arrived, looked at the computer, took out a small hammer and tapped it on the side.
Instantly the computer leapt back to life. Two days later the office manager received a bill from the consultant for $1,000.
Immediately he called the consultant and exclaimed, "One thousand dollars for fixing that computer?! You were only here five minutes! I want the bill itemized!"
The next day the new bill arrived. It read,
Tapping computer with hammer: $1
Knowing where to tap: $999