"I know how you feel", said the second dog. "My owners have a beautiful, expensive oriental rug. The other day they were late getting home from work and I just couldn't help myself... I pooped all over their nice carpet and ruined it. They're having me put to sleep, too."
Both dogs turned to the third dog in the waiting room. "So what are you here for?" they asked.
"Well," said the third dog, "my owner likes to do her housework in the nude. The other day, she was vacuuming and she knelt down to vacuum under the sofa, and I just couldn't help myself. I hopped on her back and had the ride of my life!"
The other dogs nodded in sympathy, "So she's having you put to sleep, too, huh?"
"No," said the dog, "I'm having my nails clipped."