The following are things that I've found contribute to a choice to live happily:
Act vs. React. Take control of your actions, regardless of the circumstances you are in or how much control you think you have over them. We may not be able to completely control our environment, but we can control our personal direction. When we react, we blame life; when we act we take responsibility. Which do you choose, the life of a powerless victim, or the empowering recognition that you always have choices?
Live in Today: It is O.K. to learn from the past and let those lessons affect your present, but otherwise drop the past and cease to let it control you‑‑forgive, forget, move beyond. Our bitterness, regrets, guilt, or longings for the past, are not our servants, they are our masters; revolt and flee to the present. Visions of the future are O.K. to give purpose and direction, but tomorrow is contingent on too many uncontrolled variables. Today is what you have to work with and today is where you are. Live today well, as if your visions were already coming true. Learn from the past, plan for tomorrow, but live and act today.
Recognize the Empirical Fallacy: All perception falls short of reality, regardless of how objective the intent. Nobody, short of God, has a total understanding of reality. When we realize that what we see of reality is the child of our perception, and not the other way around, we are empowered to change our perception and hence change our reality. Accepting a limitation or barrier in your life can be akin to self‑imposing such. True, we may have much work to do in order to overcome something, but we have the choice to look at it either as a prison, or as a challenge that will make us stronger. The difference has little to do with reality and everything to do with how we choose to think about it.
Live with a Purpose: Purpose is the difference between mere survival and truly living. Remember the question, "Why am I here?" and decide what direction you want to go. Dr. Victor Frankl, a WWII concentration camp survivor, believed that we can bear almost anything when we know there is purpose to our efforts. Even so, concentrate not on an end but on perfecting the journey. Purpose is more a direction than a destination.
Seek Balance: Balance and moderation are the keys to smoothing out life's ruffles. Monomaniacal fanaticism may lead to great accomplishments in one area, but always to the great loss of other potentialities. The ability to balance and juggle priorities is the key to life management. Having a multi‑faceted existence provides a broader base for dealing with setbacks and keeping successes in perspective. No one person is one person. This is not a lack of integrity, but the very beauty of life, variety. Losing integrity happens when we act contrary to our values, beliefs, and declarations. Balance is equivalent to running on all cylinders or putting all the pieces of the puzzle together. It is, put another way, personal synergism.
A good friend and I used to have a saying: "Tonight I will go home and clean up my room, my life, and make somebody happy." Translation: Cleaning up my room refers to taking charge of my reactions to what happens to and around me rather than circumstances taking charge of me; cleaning up my life refers to raising my behavior back up to my values in order to regain personal integrity; and, making somebody happy refers to serving people and developing loving relationships. When I'm not feeling up to par, I can usually find the answers in doing one or more of those three activities.