A dog was so clever that his owner sent him to college. Home for vacation, the dog admitted he had learned neither history nor science, but added proudly, “I did make a good start in foreign languages.”

“Okay,” replied the owner, “say something in a foreign language.”

The dog said, “Meow!”

One Liner
Saying “Have a nice day” sounds friendly. But saying “Enjoy your next 24 hours” sounds threatening.