Not going to confession is a huge mistake. It allows sin to ferment and allows the sinner to become comfortable with the sin. It is like the old story of the frog who was put in a pot of water and never noticed that the temperature of the water was slowly rising. The frog could have climbed out at any time and chose not to because he never realized the danger.
Sin is the same way. There are times when sin pervades the very air we breathe in this culture, and we can easily let this become true with our own lives. We get so used to it that it becomes a habit and we justify it to ourselves. Jesus, though, is Truth itself and Jesus will not allow wrongdoing to be justified. You cannot lie to Truth.
Those of us who live in areas of the world where we have access to regular confession should get on our knees and thank God for it. The Sacrament of Reconciliation imparts many graces to us to help us deal with situations where we are tempted to sin against others and against the Lord.
Here are Fr. Z’s 20 Tips For Making A Good Confession:
1) ...examine our consciences regularly and thoroughly;
2) ...wait our turn in line patiently;
3) ...come at the time confessions are scheduled, not a few minutes before they are to end;
4) ...speak distinctly but never so loudly that we might be overheard;
5) ...state our sins clearly and briefly without rambling;
6) ...confess all mortal sins in number and kind;
7) ...listen carefully to the advice the priest gives;
8) ...confess our own sins and not someone else’s;
9) ...carefully listen to and remember the penance and be sure to understand it;
10) ...use a regular formula for confession so that it is familiar and comfortable;
11) ...never be afraid to say something "embarrassing"... just say it;
12) ...never worry that the priest thinks we are jerks…. he is usually impressed by our courage;
13) ...never fear that the priest will not keep our confession secret… he is bound by the Seal;
14) ...never confess "tendencies" or "struggles"... just sins;
15) ...never leave the confessional before the priest has finished giving absolution;
16) ...memorize an Act of Contrition;
17) ...answer the priest’s questions briefly if he asks for a clarification;
18) ...ask questions if we can’t understand what he means when he tells us something;
19) ...keep in mind that sometimes priests can have bad days just like we do;
20) ...remember that priests must go to confession too … they know what we are going through.
Regarding number 14, I think the good Father was not saying we shouldn't confess sins that we struggle with, but that we should make sure to confess a specific instance of sin and not just the fact that we struggle generally with a particular type of sinfulness. The more specific we are in confession, the easier it is going to be letting go of a particular sin.
On a related note: I think many of us "modern" Catholics forget or don't realize that we are supposed to confess specific sins on a regular basis. If we have an angry outburst, for example, we shouldn't wait until we've had an angry week or month. We should get ourselves to the Sacrament as soon as possible, both for the accountability involved as well as for the grace to overcome the sin.