Terry,
Perfection is not like being a robot that does all things perfectly in a controlled environment, rather it is coming to a knowledge of God's laws, then upholding those laws by not breaking them.
It is the breaking of law that is to miss the mark of perfection. When you learn a law, you are not willingly going to break it.
I do not think that God expects us to reach perfection in the present age. It is the next age that teaches and furthers the path to perfection.
Sinning willfully is what God forbids but believers cannot stop to analyze every single they do, but if they did, they would become bogged down in their ability to function daily.
God recognizes the pitfalls of being under outside tempters. Our job is not to analyze every aspect of our lives in this present age but to pray that we do not come into temptation, and if we do, then pray that we be delivered from its clutches.
Perfection has a lot to do with knowledge, but in various degrees. The Ten Commandments were a summary of God's will and what He expected of us. More laws came that expounded on the original ten. This is because of circumstances that revolve around life in creation.