"Sin creates a proclivity to sin, it engenders vice by repetition of the same acts. This results in perverse inclinations which cloud conscience and corrupt the concrete judgment of good and evil. Thus sin tends to reproduce itself and reinforce itself, but it cannot destroy the moral sense of its root." CCC 1865
In other words, done over and over again, the act of making a decision and carrying out something contrary to good and moral thinking will make each future act of sin easier. Practice makes perfect! For years I would tell my children to practice their instruments each day, "Practice makes perfect, keep playing to get better." I would say. So they would grumble at me and head off to practice. Year after year, they would practice after my constant insistence, and year after year, they honed their craft to the point that they began to win awards, get hired to play for events, and find their voices as musicians.
Do you think repeating bad behavior, alias sinning, is any different? Likened to learning an instrument and achieving confidence and skill as a musician, sin is an act, a decision to do something..and one can get good at it! Good or bad, practice makes perfect.
This is where confession comes in; to come face to face with a bad decision and the desire for forgiveness. A chance to start over without the heavy baggage of sin. In order for forgiveness to happen, remorse must be truly internally felt with the desire to be wiped clean of the sin and be able to start over. The desire to be able to start over and get it right the next time. Just like learning an instrument, it is a conscience decision one makes from their free will. A God-given gift for a reason.
I need to go to confession.