Second, let's consider her comment about how it's up to her and John to set rules and guidelines so that he and Liz emerge from the house as worthwhile and responsible adults. That first word is VERY God-damned loaded because it says that Elly randomly damns any number of people as being completely worthless based on arbitrary, self-serving and irrational criteria. This makes her the exact opposite of the kind and fair person she tells herself she is but she doesn't admit it. Secondly, her being all over the map has so divorced Mike from understanding what cause and effect mean that when he does eventually emerge, he's completely incapable of existing in the adult world thanks to her and John's shambolic uselessness as parents.
This is because of the irresponsible and stupid way in which they wield discipline. By overreacting to non-events and letting huge problems go unnoticed, John and Elly do prove that there are worthless people out there: themselves!!