Simply from reading the Confessions very few of us have the intellectual acumen to already know how to refute the entire system en toto.
Little Sally at church has been reading _____________. She asks you questions about them. You suspect they are wrong, but not quite sure how to refute them. Since you are intellectually honest, you know that facile, simplistic answers along the lines of, "Our tradition teaches x, so he's obviously wrong" will not give her cognitive rest.
Personal anecdote: I had a dear friend of mine (who was a member of this board at one time) become infatuated with NT Wright. She asked probing questions of conservative reformed folk, and they dismissed her by saying "He's stupid. Heretic. Go read the Confession." While that may be true in the long run, that is insulting the intelligence of our bright, young minds. (She is now at Harvard Law School, fwiw).
Now, I saw the trainwreck coming. I began to discuss, calmly and without invective, the Reformed view of salvation, Wright's view, where they converge and where they diverge. She did not go over to NPP.
Now, I could have insulted her intelligence and told her to read Reformation21 Blog and not worry about stupid heretics. She would have become NPP by the end of the week (and probably rightly so). Fortunately, that didn't happen.