Lynn and Judy were doing some carpenter work on a Habitat for Humanity House. Lynn nailing down house siding, would reach into her nail pouch, pull out a nail and either toss it over her shoulder or nail it in.
Judy, figuring this was worth looking into, asked, 'Why are you throwing those nails away?'
Lynn explained, 'When I pull a nail out of my pouch, about half of them have the head on the wrong end and I throw them away.'
Judy got completely upset and yelled, 'You moron, those nails aren't defective, they're for the other side of the house!'
Hat tip: Joe of Cranky Old Man