What Makes A "Bad" Parent?

I've been wondering ever since I can remember-- What makes a "good" parent? Are there general guidelines? If so, what are they? I mean, I'm aware that you shouldn't starve or otherwise abuse your children... But what makes you Parent of the Year? If such guidelines do not exist and you are simply supposed to do the best you can then why the mom drama? I can't tell you how many times I've heard: "I can't believe she is not breast-feeding." "He's a terrible father. He has only changed two diapers today." Please, someone, help me come to some kind of consensus here...