I Started a Joke

"Shut up" I told her plainly.
     "Shut down!" She replied.
"Sto-o-o-p!" I cried.
     "Go-o-o." she mocked.
"Dog" I said
     "Cat" she called in return.
"I hate you." I grumbled.   To which she responded,  with a smile,  "I love you-u-u-u.".   And here we fell about laughing.