People who cook for dogs should go volunteer at a soup kitchen or a homeless shelter. There are people out there who deserve a meal of chicken and rice much more than your pet does.
That being said, I've given tuna juice (not the meat, just the juice that I drain off and would otherwise put down the sink) to my cats for years now. They've all lived to be a ripe old age, but it was only given as an occasional treat.
I will let my dog and cat have scraps (fat, gristle, leftover veggies, etc).