making puppies joke

A grandmother was walking with her young grandchild when they saw 2 dogs making puppies.The young child asked her grandmother what the dogs were doing.Thinking the child was too young for the truth,the woman said that the dog in back had hurt its front leg and the dog in front was towing it home.The little girl thought for a moment and turned to her grandma and said,"Isn't that the way it always goes,you stop to help someone and you end up getting screwed!!!!