Two hillbillies putting up a fence, just hammering away in the hot sun. First one starts to notice his buddy occasionally throwin' a nail over his shoulder and reaching for another.

First hillbilly says, Hey! Whatcha doin' throwin' them nails away?

They're defective, says the other hillbilly.

What?

Yup. The point is on the wrong end.

......you idjit! Quit throwin' them out! We'll use them on the OTHER side of the fence.