A guy sticks his head in the barber shop and asks, "How long before I can get a haircut?" The barber looks around the shop and says, "About two hours." The guy leaves. 
A few days later, the same guy sticks his head in the door and asks, "How long before I get a haircut?" The barber looks around the shop full of customers and says, "About two hours." The guy leaves.

A week later, the same guy sticks his head in the shop and asks, "How long before I can get a haircut?" The barber looks around the shop an says, "About an hour and half." The guy leaves. 
The barber looks over at a friend in the shop and says, "Hey Bill, follow that guy and see where he goes." 

In a little while, Bill comes back into the shop laughing hysterically. 
The barber asks, "Bill, where did he go when he left here?" 
Bill looked up and said, "To your house."