There are several ways of defining success. One, of course, is material wealth. Another is having a fulfilling job, enough money to live comfortably, a loving family and / or circle of friends. The Independent reports, people who've achieved their definition of success have chosen their friends carefully. Self made millionaires, for instance, surround themselves with optimistic people who have confidence, and a "can Do" attitude. Thomas C. Corley studied the habits of successful people for five years. He writes in his book, "Change Your Habits, Change Your Life," there's one group of people they avoid like the plague...pessimists. He reports, more than 85% of successful people associate with positive, enthusiastic people, while taking care to avoid people who exude negativity. With the new year just days away, this may be a good time for all of us to reevaluate our friendships.