Jesus said, "So be perfect, just as your heavenly Father is perfect." [Matt 5:48] Well…are you perfect? All of us have to answer no. Okay, then how "not perfect" are you?

a)        I am a good person. I don't commit many sins at all.
b)        I commit some small sins; but they are not very bad sins.
c)        I sin more than I should but I don't think I deserve hell.
d)        I'm a terrible sinner. I offend God on a daily basis.

Okay, let's see just how big a sinner you are. If you chose (a) award yourself 15 watts, for answer (b) 25 watts, answer (c) 40 watts and answer (d) 150 watts.

In a dimly lit room, you may think the room is neat and clean. When more light in brought into the room, you can see the fingerprints on the wall, the peeling paint, and the dust bunnies on the floor. Bring in still more light and you can see even minute cracks in the paint and faint streaks on the windows.

When we look into our souls, how much we see often depends on the amount of light that is available. This light comes from God through what we call our
conscience. If we routinely ignore our conscience, its ability to provide us with light diminishes. When this happens we begin to lose our appreciation for how bad sin really is. (See the lesson on Why Is Sin Such a Big Deal?)

The person who answers (a) may be a terrible sinner, but doesn't realize it because the he may have a 15-watt conscience and he is unable to see his sinfulness. The person who answers (d) may be less sinful than (a); only with his 150-watt conscience he more aware of his imperfections.
Why the Sacrament of Penance?
What does the Sacrament of Penance do for me? First, it is the means Jesus Himself designed to administer the grace of forgiveness that He earned for us on the cross. He told His apostles, "Receive the holy Spirit. Whose sins you forgive are forgiven them, and whose sins you retain are retained." [John 20:22-23] If all sins are automatically forgiven without the involvement of a minister, then such a statement by Jesus would be meaningless. Just as obviously, the minister of the sacrament needs to hear the sins in order to decide if forgiveness (or retention) is appropriate.

The Sacrament of Penance also increases our sensitivity to our own sinfulness.
What does the Church require?
The Second Vatican Council did not reduce the importance of the Sacrament of Penance to a "nice to have, but not really necessary." The Church, now as before, requires that every Catholic confess his mortal sins at least once a year.
Why do I want to go to confession frequently?
In case of mortal sin, let me ask you this. If someone said that you showed symptoms of cancer, how long would it take you to get to the doctor? It is a matter of life and death!
Now consider mortal sin. In the case of cancer, if we are too late, it will only last until we die. In the case of mortal sin, it is a matter of ETERNAL life or death! Come to the Sacrament of Penance: the Divine Physician is in.

If mortal sin is like cancer, venial sin is like a cold. No matter how many colds you get, they aren't going to kill you, but they do weaken your resistance to more serious diseases. The Divine Physician is available to help. In the case of venial sins, frequent confession provides the graces we need to resist temptation and increases the sensitivity of our consciences to the gravity of sins of any kind.

Read more about the
Sacrament of Penance at Catholic Answers.

And come
to Confession -- don't be a dim bulb!