I know how you feel, we went to Lucah's first obedience class and people don't seem to understand that dogs don't come automatically knowing how to behave, and they take some work. Most of the people in the class seem to be surprised that the dog they haven't properly socialized, or trained in anyway has issues, especially when other people come over.
I know each person in the class is a dog lover, but I shake my head when I hear the issues they are having. Most of the issues could have been prevented with some simple boundries. I commend them for coming to class, but it feels like they waited for the dog to become "bad" before they wanted to teach him how to be good.
Overall there definately is no shortage of people who don't know the difference between a dog as a companion or a dog who just lives with you.