Atonement?

Although I have only attended High Holiday events sporadically for several years, I felt like attending some this year. I went to a Rosh Hashannah service that did not require temple membership. Everyone met at a wooded site and hiked up a hill to a cabin facing a beautiful pond. The service was conducted outdoors, in front of the cabin, facing the pond. It was a pleasant experience and I enjoyed hearing and singing some of the songs I used to sing when I attended temple during my childhood. I also attended Kol Nidrei service conducted by a Jewish workshop. I enjoyed hearing the traditional song that begins the Yom Kippur holiday. However, I could not get into the prayers and did not stay much after Kol Nidrei was sung.
I have difficulty understanding the concept of atoning in one day for sins you committed during a whole year. First of all, I think it is difficult or impossible to really atone for sins against people. I know that the prayer book distinguished between sins against God and sins against people. If the sins against God involve breaking religious rules such as keeping the sabbath, putting on tfillin, or keeping kosher, then I can understand atonement. However, how can you really make up for sins against people like beating your wife or child, breaking trust, or committing crimes? It seems to me that you should not be doing such things in the first place and, if you do them, you should not be let off the hook so easily. This is the same feeling I have about Catholic confession. Once the damage is done, it is almost impossible to reverse. I think it would be better if people knew that they could never be absolved of their sins and that, in the final accounting, all the good and bad they did over the course of their lives would be weighed. As an agnostic, I do not particularly believe in the concept of a heavenly being judging whether we should go to heaven, hell, or purgatory. However, I think that for those who do believe, their behavior would be better influenced if they felt they could not get off for their sins.