Mormon 2

13 But behold this my joy was vain, for their sorrowing was not unto repentance, because of the goodness of God; but it was rather the sorrowing of the damned, because the Lord would not always suffer them to take happiness in sin.
14 And they did not come unto Jesus with broken hearts and contrite spirits, but they did curse God, and wish to die. Nevertheless they would struggle with the sword for their lives.
15 And it came to pass that my sorrow did return unto me again, and I saw that the day of grace was passed with them, both temporally and spiritually; for I saw thousands of them hewn down in open rebellion against their God, and heaped up as dung upon the face of the land. And thus three hundred and forty and four years had passed away.

Godly sorrow is different from the sorrow we so often see in the world. Sports stars, political figures, and other celebrated individuals hold press conferences to announce their regret for their behavior, but it often rings hollow. It's one thing to be sorrowful that one has offended God and family. It is entirely different to be sorry that one has been caught red-handed. Godly sorrow brings the penitent to Christ with a broken heart and a contrite spirit and results in change. Paul wrote to the Corinthians (2 Cor. 7):

10 For godly sorrow worketh repentance to salvation not to be repented of: but the sorrow of the world worketh death.
11 For behold this selfsame thing, that ye sorrowed after a godly sort, what carefulness it wrought in you, yea, what clearing of yourselves, yea, what indignation, yea, what fear, yea, what vehement desire, yea, what zeal, yea, what revenge! In all things ye have approved yourselves to be clear in this matter.

Mormon says that "the day of grace was passed with them, both temporally and spiritually." When is someone so far gone that their day of grace has passed? Only the Lord can determine that. I can understand Mormon's despair. In this one chapter he becomes a Nephite general at 16 years of age and fights in wars for the next 23 years until they sign a treaty dividing the land. I suppose after 23 years of service and effort on behalf of your people, you might be able to judge them passed their day of grace. Nevertheless, in reading on in the record, it is apparent that he didn't give up on them. He continued to serve - taught his son and undoubtedly others. And he loved the people in spite of their wickedness. Mormon's tone is sorrowful, not angry.