The moral of the story....

A grandfather and his little grandson are visiting the park in the spring, when the activity of two dogs, doing what comes naturally, catches the grandson's attention.
"Look, grandpa, look", the grandson says, pointing to the dogs.
The grandfather decides that he'd better try to get control of the situation before the kid starts asking too many embarrassing questions.
"Well, the way I see it, the one dog hurt his paw, and his friend is giving him a piggyback ride," says the grandfather.
"Isn't that the way it often is," says the grandson, "you help someone out and they wind up screwing you."