Here are some other ones:
"Don't accept your dog's admiration as conclusive evidence that you are wonderful."
Ann Landers

"If you pick a starving dog and make him prosperous, he will not bite you; that is the principal difference between a dog and a man."
Mark Twain

"No animal should ever jump on the dining room furniture unless absolutely certain that he can hold his own in a conversation."
Fran Lebowitz