It was growing cold, and a porcupine was looking for a home. He found a most desirable cave but saw it was occupied by a family of moles. 

"Would you mind if I shared your home for the winter?" the porcupine asked the moles. 

The generous moles consented and the porcupine moved in. But the cave was small and every time the moles moved around they were scratched by the porcupine's sharp quills. The moles endured this discomfort for as long as they could. Then at last they gathered courage to approach their visitor.

"Pray leave," they said, "and let us have our cave to ourselves once again." 

"Oh no!" said the porcupine. "This place suits me very well.  If you're not happy, then you should leave!"