A guy pulls into an auto repair shop.  He is frantic because his car door will not shut and he is late for work. He tells the mechanic that he needs to get to work and cannot drive because his door will not shut.  The mechanic looks at it and says that he can fix it quick and it will be $100.  The guy agrees.  The mechanic goes into his shop, picks up a hammer, and goes to the car.  After looking at it for about a minute, he carefully takes his hammer and hits one small specific area – like magic, the door opens and shuts perfectly!  The mechanic says that the charge is $100 and the guy is pissed.  It only took a minute and one swing of the hammer, how could he charge $100.  The mechanic replied that the labor was only $5, but knowing where to…