Video Meliora, proboque; Deteriora sequor

Snippet from "Fundamentals of Catholic Dogma" regarding Confession:

Perfect contrition bestows the grace of justification on the mortal sinner even before the actual reception of the Sacrament of Penance.

Imperfect contrition (attritio) is true contrition, which however springs from less perfect motives than perfect contrition. The motive of perfect contrition is the perfect love of God, i.e. Charity. It consists in this that God is loved for his Own sake above all...The love of desire, in which one loves God for one's own advantage, is primarily self-love, and therefore only secondarily imperfectly love of God. It is not a sufficient motive of perfect contrition. Perfect love however does not demand that one renounce one's own blessedness in God, but only that one's own interest be subordinated to God's interest.
__

In the Old Covenant perfect sorrow was the only means of the forgiveness of sins for adults. Cf. Ez. 18, 21 et seq. ; 33, II et seq. ; Ps. 31, 5. In the New Testament also, the operation of the forgiveness of sins, the act of sorrow of the penitent and the Church's power of the keys are brought into connection with each other...

As against Luther's assertion that contrition springing from the fear of punishment of hell makes a man a hypocrite and still more a sinner, the Council of Trent declared that this contrition "is a gift of God and a prompting of the Holy Ghost, by Whose help the penitent prepares the way to righteousness", and that it "is a true and profitable sorrow" (D 915). Thus attritio is morally good and supernatural. In many passages Holy Writ warns against sin by pointing to the Divine punishment....The Fathers also very frequently employ the fear motive...St. Augustine recommends fear of the divine punishment as means of preparing the way to the love of righteousness...If perfect contrition were necessary for valid reception the Sacrament of Penance would cease to be a Sacrament of the dead, as justification would always take place before the actual reception of the Sacrament; the power to forgive sins would lose its proper purpose, since grievous sins would never be remitted in the Sacrament of Penance.

--Ludwig Ott's "Fundamentals of Catholic Dogma"