Starting the new year requires reflecting on the past year: where we succeeded and where we failed. The new year is a blessing because, psychologically, it allows us to start over.
"OK, I did not do what I should have done last year, but I can start over this year."
But many people have trouble starting over because they are caught in the grief or rut of their mistakes. Grieving over your mistakes is good if it leads to repentance and change of behavior. Grieving over your mistakes is a waste of time if it is full of self-pity and does not lead to change. Most grieve over their mistakes in how it affected themselves, not how it affected others. When you grieve over how it affects others, that can lead to change.