Blame culture, for one thing. Books and movies that portray dogs as highly intelligent (in a human sort of way) and capable of complex planning, morally superior to many humans in their loyalty and trustworthiness. And blame us, for another. Try as we might, we have a hard time not anthropomorphizing animals in general and dogs in particular. Often without realizing it, we judge them by our own ability to learn through observation and insight, internalize values, move mentally into the future, and think abstractly—none of which dogs can do.
Two things are important here. One, that we examine our expectations of dogs to give them a realistic chance to be successful at living with us and doing the things we ask them to do. Training based on learning theory (i.e. behaviorism) is the best tool we have to understand and change the behavior of dogs, which means we need to be willing to learn about it and develop the patience and persistence to apply it. Second, that we celebrate the wonderfulness of dogs not as honorary humans but as they are. Great learners with keen olfactory senses, capable of discriminating fine differences in their environment and with a rich emotional life. In other words, marvelous creatures we are lucky to share our lives with.