"So we set out from the very beginning to get the perfect career, the perfect spouse, raise the perfect children in the perfect house, take the perfect vacations with the perfect people and die a perfect death and have a perfect funeral in a perfect funeral home with perfect flowers and perfect people saying the perfect eulogy. There is a sort of Puritanical streak in all this, and the result is a kind of neat and tidy, Pollyanna Mary Poppins perfectionism. It's pure and clean and tidy and perfect. But it is also sterile, dull, predictable and deadly.
"It is a heresy because it is a form of salvation by good works. It turns religion into a set of table manners. It tames Aslan. It confines the Holy Spirit and reduces the vital and radical religion of Jesus Christ to a code of ethics for respectable people. People wonder why the Catholic Church (or the whole Christian Church in the West for that matter) is so sick, why the young leave in droves, why there is a vocations crisis, why the liturgy seems empty and the pews are empty. The problem is complex, and the network of heresies is vast and intricately interwoven, but one of the heresies is this kind of Perfectionism."
Go here for the whole convicting thing.