Being a jerk is similar in many ways to being an alcoholic. Jerks tend to be loud, and are oblivious to the way their selfish, subjective, behavior annoys those around them. Once you've been a jerk for an extended period of time, you are a jerk for life. Although, you may learn to gain control over the condition once you've recognized the problem.
I personally, have learned to second guess everything i say and do. I have to be careful, because often my first reaction in a given situation is the subjective, "jerky" one. Quiet reflection has become an essential aid in this aspect of "rehabilitation".
I envy the people who look back on their younger years with warm nostalgia. I now objectively look back on mine with revulsion and regret. While guilt and regret can easily turn self indulgent and morbid, they can also be a great starting point to realizing a different approach to life is required if one ever expects to find peace.