By the Grace of God

So today I was contemplating after Mass whether or not it is that everybody is accountable for what they do. Biologists and Psychologists suggest that there's a lot that we do that we have no control over. Some people believe in fate, and all Christian believers posit God as omniscient, knowing exactly what we're going to do.
For this reason I was once told that the only true prayer that we can pray is "Fiat voluntas tuas" (Thy will be done). If this is the truth, the only answer, is there hope for us?
To return to the first question, one must consider those who might be argued to not be accountable. Among these are the mentally unstable, the mentally handicapped, and young children. If we suggest this, then, what separates somebody who is accountable from somebody who isn't? Is there some kind of defining moment when we become accountable or some stack of characteristics? Whenever I made trouble for myself as a child, my parents always said, "You should know better." So was I more accountable than others who might have done the same things?
Ultimately, I believe we are accountable to God. Yes, we have laws and legal systems to ensure people's safety and the well-being of society. However, they are flawed, and unless there truly is no justice in the world, the only person we are must answer to for all that we do is the ultimate power over all the universe.
So what about those that seem as if they are unable to actually do what they should? What about those who seem utterly helpless and irresponsible? Well, my belief is that they indeed are accountable. No man is completely innocent of all faults. No human being by his or herself is able to overcome all vices and sins. Sometimes what we need to do is ask for help.
So, it is my firm belief that for those who feel that they are helpless, there is indeed help. For those who feel irresponsible and unable to enact change, there is a source they can turn to for guidance. Sometimes it takes prayer, and sometimes it takes asking for help from fellow human beings.
However, above all, one cannot change his or her ways unless he or she is willing to forsake what it is that impedes them. If we make no conscious effort ourselves, we can do nothing. So, when we pray "Thy Will be done" we must remember that we ourselves are willing God's will. We are showing our own desire to be what God wills us to be. If we refuse to change, we cannot, with any truthfulness, ask anything of God.