When people come to confession they often have something on their conscience which makes them feel guilty, ashamed or scared.
Most often this is something where they’ve lost control. Maybe it is a sin that is ‘below the belt’, something to do with food, drink or drugs, losing one’s temper, being violent etc. This sin of passion makes them feel guilty or ashamed or scared, but despite their strong feelings it may not be the most serious sin, or the thing which is keeping them from God.
The amount of guilt we feel or don’t feel does not necessarily reflect accurately the seriousness of our sin.
This is why an examination of conscience is so necessary. A good examination of conscience (and you can find them online or in any good Catholic prayer book) makes things much more objective. The questions simply take us through what we’ve done and what we’ve left undone so that we can come to confession simply, objectively and honestly. We do need to confess the things we’re ashamed of, but we also need to consider the amount of guilt and shame we feel with some distance.
The dirty shameful thing we did may not be as serious an offense as the harsh word, the hardened heart or the lack of prayer or love for God which we don’t feel guilty about at all.
In many ways confession should be like a visit to the dentist. When you go to the dentist you don’t wring your hands and feel terribly guilty about tooth decay. Neither does your dentist make you feel bad or decide to drill without novacaine to teach you a lesson. No, you ask for him to examine you. He says there is tooth decay and he needs to drill and fill. That’s that.
Likewise with soul decay. You admit you have soul decay because of sin. The priest listens to your confession. (That’s like the examination) He gives you penance (that’s like the drilling) then he pronounces absolution (and the grace you receive is like that new filling)