A little boy, about 5 years of age, walks into a convenience store and asks the salesclerk, "Got any grapes?"
"No," answers the clerk. The boy walks out.
A little later he returns and asks, "Got any grapes?"
The clerk replies, "No! Like I told you fifteen minutes ago, I don't have any grapes!"
The boy leaves. Fifteen minutes later he's back again, asking, "Got any grapes?"
In a real snit now, the clerk yells, "No I don't have any darn grapes! You come back in here again, I'll nail your tiny feet to the floor!"
Later that day the boy comes back to the convenience store and asks the clerk, "Got any nails?"
The clerk shouts, "No!"
The boy replies, "Good! Got any grapes?"