When I went to school, I learned that sin was breaking God's law. As an adult, I realize that sin must be understood in relation to God's love. In the Scriptures and in the experiences of our daily lives, we see how much God has loved us and continues to care for us. When we examine our lives in the light of God's love, we come to realize that our love for God, our neighbor and ourselves falls far short of God's love for us. The creator calls us to life, growth and wholeness.
Sin is the refusal of that gift of life and call to growth.
To be aware of sin, we must first be aware of God's love. Those who do not see the constant role that God plays in their lives are not aware of sin. Even if your priest does not include a reading during the sacrament, you might consider reading the parable of the prodigal son or some other Scripture in preparation for the sacrament. Or you may find the Our Father an appropriate act of contrition. The priest then prays the prayer of absolution.