An overheard line, reported in the NYT's Metropolitan Diary.
I'm no dog expert, but this one is easy. The way a dog knows it's cute is that the people continually tell it it's cute. The same thing happens with children too. If you don't want to find yourself living with a dog/child that knows it's cute, you need to keep a straight face about the cuteness. That will preserve the cuteness of the cuteness.