Two blondes, Becky and Sally, were putting siding on a house.
Becky, who was nailing down the siding, would reach into her nail pouch, pull out a nail and either toss it over her shoulder or nail it in.
Sally, wondering what she was doing, asked, "Why are you throwing away all those nails?"
Becky explained, "When I pull a nail out of my pouch, about half of them have the head on the wrong end, so I throw them away."
Sally got completely upset and yelled, "You moron! Those nails aren't defective, they're for the other side of the house!"