Why do we "repent"?

Last week I was doing catechism questions with Elisabeth from My First Book of Questions, and came to the question, What does it mean to repent?

After we had discussed the question and answer, I asked Elisabeth, 'Why do we repent?', to which she promptly responded,

"To get dessert!"

Earlier that evening at the table, she had had a bad attitude, and I had told her that it needed to change if she was going to join us for dessert. She changed her attitude, and finished her food - and clearly internalized the reason for her repentance. Her transparent answer showed what many of us exhibit: no hatred of sin or desire to be done with it. Yet that very honesty provides the opportunity for true repentance to occur.