In the interests of accuracy, I’d like to re-emphasize what you alluded to earlier - formal confession applies to Mortal Sins. Formal confession is NOT required for Venial sins, even though it is strongly recommended.
Mortal sin, like fire, has three elements. These three are Grave Matter, Full Knowledge, and Deliberate (Complete) Consent. Absent one of the three elements, even if the matter is grave, it is not mortal sin. (Catechism of the Catholic Church, paragraphs 1854-1864)
Furthermore, formal confession and absolution is an all-or-nothing act. There is no provision for confessing some sins and withholding others for additional study. That condition, which seems daunting, is actually the most liberating part of confession and absolution. As you said, this is a beautiful thing.
Catechism of the Catholic Church
1456 Confession to a priest is an essential part of the sacrament of Penance: "All mortal sins of which penitents after a diligent self-examination are conscious must be recounted by them in confession, even if they are most secret and have been committed against the last two precepts of the Decalogue; for these sins sometimes wound the soul more grievously and are more dangerous than those which are committed openly."
When Christ’s faithful strive to confess all the sins that they can remember, they undoubtedly place all of them before the divine mercy for pardon. But those who fail to do so and knowingly withhold some, place nothing before the divine goodness for remission through the mediation of the priest, “for if the sick person is too ashamed to show his wound to the doctor, the medicine cannot heal what it does not know.”
1457 According to the Church’s command, “after having attained the age of discretion, each of the faithful is bound by an obligation faithfully to confess serious sins at least once a year.” Anyone who is aware of having committed a mortal sin must not receive Holy Communion, even if he experiences deep contrition, without having first received sacramental absolution, unless he has a grave reason for receiving Communion and there is no possibility of going to confession. Children must go to the sacrament of Penance before receiving Holy Communion for the first time.
1458 Without being strictly necessary, confession of everyday faults (venial sins) is nevertheless strongly recommended by the Church. Indeed the regular confession of our venial sins helps us form our conscience, fight against evil tendencies, let ourselves be healed by Christ and progress in the life of the Spirit. By receiving more frequently through this sacrament the gift of the Father’s mercy, we are spurred to be merciful as he is merciful.