Hammerheads

Two blondes are working on a house. One of them, who’s nailing down siding, has been reaching into her pouch, pulling out a nail, and either tossing it over her shoulder or nailing it in. The second blonde, figuring this was worth looking into, asks, "Hey—how come you’re throwing half the nails over your shoulder?"
The first blonde explains, "If I pull a nail out of my pouch and it’s pointed toward me, I throw it away because it’s defective. If it’s pointed toward the house, then I nail it in."
"You moron!" the second blonde yells. "The nails pointed toward you aren’t defective. They’re for the other side of the house.