There's a great site with lots of info on why dogs behave the way that they do, as well as how to train them like a Good Pack Leader over at Paw Persuasion. Written by Rena Murray, it's filled with great stuff for dog owners, such as:
Remember your dog is a dog, not a "fur person" (to borrow from Susan Conant in Gaits of Heaven);
your dog must respect you and this is shown in specific canine behaviors; and
the top three reasons that humans cater to dogs.