A old couple were sitting on the porch

An old couple were sitting on the porch one afternoon rocking in their rocking chairs.

All the sudden the old man reaches over and slaps his wife.

She says, “Well what was that for?”

He says, “That’s for 40 years of rotten lovemaking!”

She doesn’t reply and they start rocking again.

All the sudden the old lady reaches up and slaps her husband.

He says, “Well what was that for?”

She says, “That’s for knowing the difference!”