From David Letterman:

Top Ten Signs You Have a Dumb Dog

10. Lengthy pause after "bow" while it tries to remember "wow"
9. Buries tail, wags bones
8. When you give him Alpo, he just eats the meat-by-products
7. Despite the overwhelming evidence, still smokes two packs a day
6. Showed up at the Whoopi Goldberg roast in catface
5. Has suffered over two dozen concussions from toilet seat falling on his head
4. Thinks "Snausages" is a real word
3. Voted for Fred Grandy, Love Boat's Gopher, because he really thought he'd be a good Congressman
2. Spends hours staring at kitchen cabinet, waiting for tiny horse-and-carriage to come out
1. Constantly chasing people named "Katz"