are the parents that aren't doing their job as parents by supporting the work of the teachers. They tend to be the ones who complain the most when their child doesn't do well on an assignment/course or who isn't allowed to make up work that was supposed to be turned in weeks ago. They are the parent that complains to the principle when their child gets in trouble, who doesn't believe their child could be a trouble maker, and who doesn't agree with any punishment their child gets.
Teachers spend too much time dealing with crappy parents.