The following comes from "A Collection of Thoughts on Life" by Dale Brown. I believe in this philosophy because I worked for Coach Brown for over a decade and saw him live this very philosophy each and every day.
So much of life comes from our views and beliefs and I can't imagine living life to its fullest without a positive attitude. The best part of our attitude is that we decide what type of attitude we want to display. This is so difficult for many to believe, but if you have a bad attitude, it is because you choose to have one. People are not born with positive mental attitudes. Somewhere down the road, at some point in your life, for whatever reason it may have been, they choose to look at the positive side of all the circumstances surrounding their life. That doesn't mean they don't have a bad day or that they never get angry or depressed. Those are all human emotions that each and every one of us must deal with the negative in a much different manner than if you have a poor attitude. A poor attitude will throw gas on the fire of negative happenings. A good attitude will throw water on that same fire and put it out.
Something to remember in cultivating a positive attitude is to always be full of enthusiasm. Enthusiasm and positive attitudes feed off each other. If you are enthusiastic, you will look at things in a positive light. If you have a positive attitude, you will find enthusiasm much quicker. I don't think I have ever met a person with a positive attitude that wasn't beaming full of overwhelming enthusiasm. These kind of people are contagious. They spread this exciting feeling to those around them and soon there is an epidemic started. A positive epidemic!