An old couple was sitting on the porch in their rockers, when the wife took her cane and hit him on the head as hard as she could.

After he got over the stun he asked,"What was that for?"

"That's for all the bad sex you've been giving me over the years", she replied. After a while the husband took his cane and hit her so hard it knocked her completely out of the chair.

As she got back in the chair and gathered herself she asked,"Now what was that for?"

He replied, "For knowing the difference."