Yes parents evenings can be stressful! Having been on both sides of the fence with one " difficult" and one compliant child it is difficult to know sometimes. I always saw the relationship between parents and teachers as a partership, if an unequal one. Some parents would do anything to help their child others virtually nothing, either because they lacked the parenting skills or they expected you to do it all, " you are the teacher after all"
The same can be said of teachers of course. Some are great at motivation and others just teach. I worked abroad for a few years and found that in both countries teachers were experts at their subject but were not expected to be social workers, very different to here. Although with the advent of the national curriculum pastoral care has disappeared from a lot of schools, it doesn't figure in the league tables!
As an observation problem parents often didn't show up to parent evenings because they didn't care much about their kids or school, and this could explain the childs indifference to work.
As for success at uni or in a job thats another question? Many students grow up and realise whats important and start using the talents they wasted at school.