The one who was nailing down siding would reach into her nail pouch, pull out a nail and either toss it over her shoulder or nail it in.

The other, figuring this was worth looking into, asked, “Why are you throwing those nails away?”

The first explained, “If I pull a nail out of my pouch and it’s pointed toward me, I throw it away ’cause it’s defective. If it’s pointed toward the house, then I nail it in!”
…

The second blonde got completely upset and yelled, “You moron! The nails pointed toward you aren’t defective! They’re for the other side of the house!”