An old couple was sitting on the porch one afternoon rocking in their rocking chairs All of a sudden he reaches over and slaps his wife She says to him "what was that for" He says "That's for 40 years of rotten sex" She doesn't reply and they start rocking again All of a sudden the old lady reaches up and slaps her husband He says to her "What was that for? " She says that's for knowing the difference!"