Though we each have a complicated psychological code to decipher, the Torah assures us that we are each capable of breaking our personal code. Though it is difficult, it is not beyond us, particularly during this special time preceding Rosh Hashonah. HaRav Simpson Raphael Hirsh notes that the Vidduy is not simply a confession of one's sins to Hashem, but is also a confession of sins to ourselves. Without personally facing our own ego, we can never truly improve. Thus, the first step is our personal confrontation with the sins we confess in the Vidduy.
Unity gives strength.
You are standing this day, all you before the L-rd, your heads, your tribes, your Elders and your officers, every man of Israel. When they are together. A covenant with all Jews. Rashi comments that this refers to future generations. Similarly, while the future generations were not physically present, the genetic bases that would later produce them were present in that generation of Jews.