Guilt: we're wired for it. Proof the Yom Kippur is necessary as a psychologically restorative event:
Guilt and Atonement on the Path to Adulthood
"Guilt in its many varieties — Puritan, Catholic, Jewish, etc. — has often gotten a bad rap, but psychologists keep finding evidence of its usefulness. Too little guilt clearly has a downside — most obviously in sociopaths who feel no remorse, but also in kindergartners who smack other children and snatch their toys. Children typically start to feel guilt in their second year of life, says Grazyna Kochanska, who has been tracking children’s development for two decades in her laboratory at the University of Iowa. Some children’s temperament makes them prone to guilt, she said, and some become more guilt-prone thanks to parents and other early influences.
"... She recommends focusing not just on the bad deed, but more important, on how to make amends. “Both children and adults can be surprisingly clueless about whether and how to make things right,” Dr. Tangney said. “Little kids are overwhelmed by the spilled mess of milk on the floor. Parents can teach and support them to say ‘I’m sorry’ and to clean it up, maybe leaving the kitchen a little cleaner than it was before.”
So, lest we get tired of all that repetitive breast-beading during the Vidui, we're now backed by science. It really will help make us feel better.