Sin and guilt.. and damnation?

In writing a work of Catholicism, presumably with intent to not only vent and cleanse himself of what he believes were despicable actions, yet also, perhaps, convert others to the Catholic faith, his prolific use of sin, in my view, is beneficial.

After all, the audience choosing to read Augustine back in the fourth century was most probably educated and searching for an apt faith, maybe even salvation, themselves. The concept of "sin" was recurrent, as we see through examples of the sect of the Manichees (ex. of sacrificing animals, etc.). 'Sin' might have been regarded actions that isolate the individual from the divine, from the ruler of the Earth, the creator. In this context it would be deemed problematic and necessary to fix in human beings. Augustine offers a path of reflection to recover from one's presumed sins, a path which will hopefully purge and purify the individual and foster a stronger connection to God.

Although, I believe Belle from The Drama Queen's Apartment brought up a solid point:

Instead of guilting or scaring people into changing their religious beliefs, he should try to open their eyes to the good things that a life with God could bring them.

In modern day religion, I perceive, individuals are oftentimes "guilted" into religious practice.
People go to Confession, although they often find it useless (but necessary). Even I am guilt-tripped into attending church by my parents. (All this is at least applicable to my experience in Catholic faith, yet I'm inclined to believe young individuals from different backgrounds might have similarly diverging ideas from that of their parents'). Religious freedom of course is a major component of our American society, but arising from a deeply-rooted religious background, it is not easy to cut ties and abandon the familial religion. In doing so, seclusion and outcasting from the family is imminent.

Yet somehow, based on Augustine's account, it appears the separation was much freer in his day. It is true that his mother wept over his conversion, yet she and her ideology evidently had not exerted enough pressure to return him to the Catholic faith. Only upon developing his own ideas of the faith was Augustine a true believer... which I find slightly comical. Augustine is a saint within the Catholic religion, but was it not essentially his creation? And don't we always find our own ideas appealing? And our own determined path, easy to follow? (I don't know, a google search for "why is Augustine saint" had not produced many results. Much ignorant of the actual procedure for declaring sainthood, I'll continue with my research).

It's a much different psychological occurrence when we are introduced to or forcefully submerged in ideas that are not our own proud creations but modes of thinking esteemed to be moral, correct, righteous.

Also, what role did guilt of sin take back in Augustine's day? I'd guess that the public's perceptions of sinfulness and right-of-way were more lenient and subjective as opposed to today's for the developing religious structures, such as of Catholicism, and existent paganism as well as sects.

Yet returning to my initial statement, I believe that with regards to academics who would peruse Augustine's work, the repeated mentions of 'sin' were effective, for these individuals exposed themselves voluntarily to a work, maybe in hope of finding an inner spiritualism. Maybe without the developed-Medieval concepts of Christianity they weren't necessarily guilt-ridden, rueful, and afraid of eternal damnation. Maybe they were just searching and dipping their feet into a system of beliefs that would soon, inevitably, rule the world.