Two blondes were working on a house. The one who was nailing down the skirting boards would reach into her nail pouch, pull out a nail and either toss it over her shoulder or nail it in.

The other blonde asked, what she was doing

The first blonde explained,

"If I pull a nail out of my pouch and it's pointed TOWARD me I throw it away because its made the wrong way round and won't go into the wall. If it's pointed toward the HOUSE wall then it's obviously not defective and I nail it in!"

The second blonde got angry and yelled,

"You MORON!!! The nails pointed toward you aren't defective! They're for the OTHER side of the house!!"