But hey, in dogs and cats? I've learned to love cats, but not all my readers have. So for you doggie-lovers (and, btw, I love a well-trained dog, myself), here's a vid on Border Collies.
(Their embed code may/may not work; so here's the vid.)
Sounds like a great dog if you're outdoors a lot; not so much a house-dog. Hear some owners' comments here.
Finally, I may have linked to this before, but here are some shepherds and their dogs having buckets of fun: